Fluid displacement energy storage

ABSTRACT

A system for storing and generating power is disclosed. The system comprises a first storage reservoir configured to store a first fluid, a second storage reservoir located at a lower elevation than the first storage reservoir and configured to store a second fluid wherein said second fluid has a higher density than the first fluid, and a pump. In some embodiments a generator may be employed. The pump and the first and the second reservoir are operatively connected such that power is stored by displacing the second fluid in the second storage reservoir by pumping the first fluid from the first storage reservoir to the second storage reservoir and such that power is generated by allowing the pumped first fluid in the second storage reservoir to exit the second reservoir. The first fluid is generally a liquid.

CROSS REFERENCE TO RELATED APPLICATIONS

The instant application is a continuation-in-part of U.S. applicationSer. No. 17/665,472 filed Feb. 4, 2022 which application is acontinuation-in-part of PCT/US21/41931 filed Jul. 21, 2021 published asWO2022/016034 which PCT application claims priority to U.S. applicationSer. No. 17/214,100 filed on Mar. 26, 2021 which is acontinuation-in-part application of U.S. application Ser. No. 16/932,429filed Jul. 17, 2020. The application also claims priority to U.S.application No. 63/117,355 filed Nov. 23, 2020; U.S. application No.63/132,778 filed Dec. 31, 2020 and U.S. application No. 63/139,157 filedJan. 19, 2021. The application also claims priority to U.S. applicationNo. 63/249,100 filed Sep. 28, 2021 titled FLUID DISPLACEMENT ENERGYSTORAGE FOR DESALINATION APPLICATION AND FLOW BATTERY APPLICATION. Theapplication also claims priority to U.S. application No. 63/272,760filed Oct. 28, 2021 tided FLUID DISPLACEMENT ENERGY STORAGE. All of theaforementioned applications are hereby incorporated by reference intheir entirety.

SUMMARY OF INVENTION

The present invention relates to systems and methods for energy storage,or energy generation, or combinations thereof.

Some embodiments may be applicable to, for example, an energy storagedevice. Some embodiments may involve a storage reservoir at a higherelevation, or a higher elevation reservoir, and a storage reservoir at alower elevation, or lower elevation reservoir. The higher elevationreservoir may be at a higher elevation than the lower elevationreservoir. Energy or power may be stored, or the energy storage systemmay be ‘charged’, by pumping a low density fluid from a higher elevationreservoir into the lower elevation reservoir, where the low densityfluid displaced high density fluid in the lower elevation reservoir. Insome embodiments, displaced high density fluid may exit the lowerelevation reservoir. In some embodiments, displaced high density fluidmay be transferred to the higher elevation reservoir. In someembodiments, displaced high density fluid may be transferred to thehigher elevation reservoir in a closed system. In some embodiments,energy may be released or power may be generated, or the energy storagesystem may be ‘discharged’, by allowing high density fluid to displacelow density fluid in the lower elevation reservoir. In some embodiments,energy may be released or power may be generated, or the energy storagesystem may be ‘discharged’, by allowing high density fluid to displacelow density fluid in the lower elevation reservoir and transferring thedisplaced low density fluid to the higher elevation reservoir. In someembodiments, energy may be released or power may be generated, or theenergy storage system may be ‘discharged’, by allowing high densityfluid to displace low density fluid in the lower elevation reservoir andtransferring the displaced low density fluid to a power recovery device,such as an electrical generator, or electrical turbine, or pressureexchanger, or any combination thereof. In some embodiments, energy maybe released or power may be generated, or the energy storage system maybe ‘discharged’, by allowing high density fluid to displace low densityfluid in the lower elevation reservoir, wherein the displaced lowdensity fluid comprises high pressure low density fluid. In someembodiments, energy may be released or power may be generated, or theenergy storage system may be ‘discharged’, by allowing high densityfluid to displace low density fluid in the lower elevation reservoir andtransferring the displaced low density fluid into a power conversionprocess, such as an electrical generator, or electrical turbine, orpressure exchanger, or a desalination process, or any combinationthereof.

In some embodiments, the higher elevation storage reservoir may be nearthe elevation of the surface of a body of water. In some embodiments,the higher elevation storage reservoir may be at an elevationsubstantially greater than the elevation of the surface of a body ofwater. In some embodiment, the higher elevation storage reservoir may beat an elevation below the surface of a body of water. In someembodiments, the higher elevation storage reservoir may be floating. Insome embodiments, the higher elevation storage reservoir may be on land.In some embodiments, the higher elevation storage reservoir may be on aplatform above a body of water. In some embodiments, the higherelevation storage reservoir may be floating or suspended beneath thesurface of a body of water. In some embodiments, the higher elevationstorage reservoir may be located on the seabed or land beneath thesurface of a body of water.

In some embodiments, the lower elevation storage reservoir may be nearthe elevation of the surface of a body of water. In some embodiments,the lower elevation storage reservoir may be at an elevationsubstantially greater than the elevation of the surface of a body ofwater. In some embodiment, the lower elevation storage reservoir may beat an elevation below the surface of a body of water. In someembodiments, the lower elevation storage reservoir may be floating. Insome embodiments, the lower elevation storage reservoir may be on land.In some embodiments, the lower elevation storage reservoir may be on aplatform above a body of water. In some embodiments, the lower elevationstorage reservoir may be floating or suspended beneath the surface of abody of water. In some embodiments, the lower elevation storagereservoir may be located on the seabed or land beneath the surface of abody of water.

Some embodiments may be applicable to, for example, desalination. Forexample, some embodiments may relate to employing energy stored in theenergy storage system to power desalination. For example, someembodiments may relate to pressure exchanging low density fluid in theenergy storage system with desalination feed water, which may result inthe pressurization of desalination feed water and/or supplying asubstantial portion of the energy required in desalination. For example,some embodiments may relate to employing desalination feed water as thelow density fluid in an energy storage system. For example, someembodiments may relate to employ water, or aqueous solutions, as the lowdensity fluid, or high density fluid, or any combination thereof in anenergy storage system. For example, some embodiments may relate topowering desalination with an energy storage system, wherein the lowdensity fluid, or high density fluid, or any combination thereof arechemically different than the desalination feed water.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 : Storage tank or storage unit configured to store high densityfluid and low density fluid, wherein the high density fluid and lowdensity fluid are separate due to a fluid-fluid interface, or cline, orany combination thereof, and wherein low density fluid is entering andhigh density fluid is exiting.

FIG. 2 : Storage tank or storage unit configured to store high densityfluid and low density fluid, wherein the high density fluid and lowdensity fluid are separate due to a fluid-fluid interface, or cline, orany combination thereof, and wherein low density fluid is exiting andhigh density fluid is entering.

FIG. 3 : Storage tank or storage unit configured to store high densityfluid and low density fluid, wherein the high density fluid and lowdensity fluid are separate due to a floating barrier, and wherein lowdensity fluid is entering and high density fluid is exiting.

FIG. 4 : Storage tank or storage unit configured to store high densityfluid and low density fluid, wherein the high density fluid and lowdensity fluid are separate due to a floating barrier, and wherein highdensity fluid is entering and low density fluid is exiting.

FIG. 5 : An embodiment with a higher elevation reservoir on land, alower elevation reservoir underwater, and a pressure exchanger locatedbetween the higher elevation reservoir and lower elevation reservoir,and wherein energy is being stored or the system is ‘charging’.

FIG. 6 : An embodiment with a higher elevation reservoir on land, alower elevation reservoir underwater, and a pressure exchanger locatedbetween the higher elevation reservoir and lower elevation reservoir,and wherein energy is charged or nearly fully charged.

FIG. 7 : An embodiment with a higher elevation reservoir on land, alower elevation reservoir underwater, and a pressure exchanger locatedbetween the higher elevation reservoir and lower elevation reservoir,and wherein energy is be generated or the system is ‘discharging’.

FIG. 8 : An embodiment with a higher elevation reservoir on land, alower elevation reservoir underwater, and a pressure exchanger locatedbetween the higher elevation reservoir and lower elevation reservoir,and wherein the system is discharged or nearly fully discharged.

FIG. 9 : An embodiment with a higher elevation reservoir floating onwater, a lower elevation reservoir underwater, and a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein energy is being stored or the system is‘charging’.

FIG. 10 : An embodiment with a higher elevation reservoir floating onwater, a lower elevation reservoir underwater, and a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein energy is being stored or the system is chargedor nearly fully charged.

FIG. 11 : An embodiment with a higher elevation reservoir floating onwater, a lower elevation reservoir underwater, and a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein energy is be generated or the system is‘discharging’.

FIG. 12 : An embodiment with a higher elevation reservoir floating onwater, a lower elevation reservoir underwater, and a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the system is discharged or nearly fullydischarged.

FIG. 13 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir and lower elevation reservoir comprise multiplestorage units configured to store low density fluid and high densityfluid.

FIG. 14 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir and lower elevation reservoir comprise multiplestorage units configured to store low density fluid and high densityfluid.

FIG. 15 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir and lower elevation reservoir comprise multiplestorage units configured to store low density fluid and high densityfluid.

FIG. 16 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir and lower elevation reservoir comprise multiplestorage units configured to store low density fluid and high densityfluid.

FIG. 17 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 18 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 19 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid,

FIG. 20 : An embodiment with a higher elevation reservoir floating onwater and a lower elevation reservoir underwater, wherein the higherelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 21 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the higher elevation reservoircomprises storage units designed to store high density fluid separatefrom low density fluid.

FIG. 22 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the higher elevation reservoircomprises storage units designed to store high density fluid separatefrom low density fluid.

FIG. 23 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the higher elevation reservoircomprises storage units designed to store high density fluid separatefrom low density fluid.

FIG. 24 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the higher elevation reservoircomprises storage units designed to store high density fluid separatefrom low density fluid.

FIG. 25 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir comprises storageunits designed to store high density fluid separate from low densityfluid.

FIG. 26 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir comprises storageunits designed to store high density fluid separate from low densityfluid.

FIG. 27 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir comprises storageunits designed to store high density fluid separate from low densityfluid.

FIG. 28 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir comprises storageunits designed to store high density fluid separate from low densityfluid.

FIG. 29 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 30 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 31 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 32 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprises storage units designed to store highdensity fluid separate from low density fluid.

FIG. 33 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprise storage units designed to store highdensity fluid and low density fluid.

FIG. 34 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprise storage units designed to store highdensity fluid and low density fluid.

FIG. 35 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprise storage units designed to store highdensity fluid and low density fluid.

FIG. 36 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir on land, wherein there is a pressure exchangerlocated between the higher elevation reservoir and lower elevationreservoir, and wherein the higher elevation reservoir and lowerelevation reservoir comprise storage units designed to store highdensity fluid and low density fluid.

FIG. 37 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underground, and wherein the lower elevationreservoir is designed to store high density fluid and low density fluid.

FIG. 38 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underground, and wherein the lower elevationreservoir is designed to store high density fluid and low density fluid.

FIG. 39 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underground, and wherein the lower elevationreservoir is designed to store high density fluid and low density fluid.

FIG. 40 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underground, and wherein the lower elevationreservoir is designed to store high density fluid and low density fluid.

FIG. 41 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, and wherein the elevation of thehigher elevation reservoir is substantially greater than the elevationof the water level of the body of water.

FIG. 42 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, and wherein the elevation of thehigher elevation reservoir is substantially greater than the elevationof the water level of the body of water,

FIG. 43 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, and wherein the elevation of thehigher elevation reservoir is substantially greater than the elevationof the water level of the body of water.

FIG. 44 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, and wherein the elevation of thehigher elevation reservoir is substantially greater than the elevationof the water level of the body of water.

FIG. 45 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 46 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 47 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 48 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 49 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir at an elevation near the elevation of the waterlevel of the body of water, and wherein the elevation of the higherelevation reservoir is substantially greater than the elevation of thewater level of the body of water,

FIG. 50 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir at an elevation near the elevation of the waterlevel of the body of water, and wherein the elevation of the higherelevation reservoir is substantially greater than the elevation of thewater level of the body of water.

FIG. 51 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir at an elevation near the elevation of the waterlevel of the body of water, and wherein the elevation of the higherelevation reservoir is substantially greater than the elevation of thewater level of the body of water.

FIG. 52 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir at an elevation near the elevation of the waterlevel of the body of water, and wherein the elevation of the higherelevation reservoir is substantially greater than the elevation of thewater level of the body of water.

FIG. 53 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir at an elevation near the elevation of the waterlevel of the body of water, and wherein the elevation of the higherelevation reservoir is substantially greater than the elevation of thewater level of the body of water.

FIG. 54 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 55 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 56 : An embodiment with a higher elevation reservoir on land and alower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 57 : An embodiment with a higher elevation reservoir underwater anda lower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 58 : An embodiment with a higher elevation reservoir underwater anda lower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 59 : An embodiment with a higher elevation reservoir underwater anda lower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 60 : An embodiment with a higher elevation reservoir underwater anda lower elevation reservoir underwater, wherein there is a pressureexchanger located between the higher elevation reservoir and lowerelevation reservoir, and wherein the elevation of the higher elevationreservoir is substantially greater than the elevation of the water levelof the body of water.

FIG. 61 : An embodiment with a pump and/or turbine and/or generatorlocated near the lower elevation reservoir and fluidly connected to thehigh density fluid.

FIG. 62 : An embodiment with a pump and/or turbine and/or generatorlocated near the lower elevation reservoir and fluidly connected to thehigh density fluid.

FIG. 63 : An embodiment with a pump and/or turbine and/or generatorlocated near the lower elevation reservoir and fluidly connected to thehigh density fluid.

FIG. 64 : An embodiment with a pump and/or turbine and/or generatorlocated near the lower elevation reservoir and fluidly connected to thehigh density fluid.

FIG. 65 : Energy Storage Charging, Desalination Powered by ExternalSource

FIG. 66 : Energy Storage Steady State, Desalination Powered by ExternalSource

FIG. 67 : Energy Storage Discharging, Desalination Powered by PressureExchange with High Pressure Low Density Fluid Produced by DischargingEnergy Storage System

FIG. 68 : Energy Storage Steady State, Desalination Powered by PressureExchange with Recirculating Low Density Fluid

FIG. 69 : Energy Storage Charging, Desalination may be Powered byPressure Exchange a Portion of High Pressure Low Density Fluid Producedby Energy Storage System Charging, a Portion of Low Density Fluid may beRecirculated

FIG. 70 : Energy Storage Discharging, Splitting High Pressure LowDensity Fluid Stream to Power Simultaneous Electricity Generation andDesalination

FIG. 71 : Energy Storage Charging, Desalinating Water with ExternalPower Source, Embodiment with Direct Fluid Displacement in LowerElevation Reservoir

FIG. 72 : Energy Storage Charging, Desalinating Water with ExternalPower Source with Separate Pump from Energy Storage Pump

FIG. 73 : Energy Storage Charging, Desalinating Water with Same Pump asEmployed in Energy Storage or Same Fluid as Low Density Fluid Employedin Energy Storage or any Combination Thereof

FIG. 74 : Energy Storage Steady State, Desalinating Water with ExternalPower Source

FIG. 75 : Energy Storage Steady State, Pressurizing Desalination FeedWater using Same Pump as is Employed in Energy Storage

FIG. 76 : Energy Storage Discharging, High Pressure Low Density Fluidfrom Discharging Employed as at Least a Portion of PressurizedDesalination Feed Water

FIG. 77 : Energy Storage Discharging, High Pressure Low Density Fluidfrom Discharging Employed as at Least a Portion of PressurizedDesalination Feed Water

FIG. 78 : Energy Storage Discharging, High Pressure Low Density Fluidfrom Discharging Employed as at Least a Portion of PressurizedDesalination Feed Water and for Power Generation

FIG. 79 : Energy Storage Discharging, High Pressure Low Density Fluidfrom Discharging Employed as at Least a Portion of PressurizedDesalination Feed Water and for Power Generation

FIG. 80 : Energy Storage Charging, Desalinating Water with ExternalPower Source, Embodiment may comprise Direct Fluid Displacement in LowerElevation Reservoir

FIG. 81 : Energy Storage Charging, Desalinating Water with same PumpEmployed in Energy Storage, or a Portion of the High Pressure LowDensity Fluid Comprising Desalination Feed Water, or any combinationthereof, Embodiment may comprise Direct Fluid Displacement in LowerElevation Reservoir

FIG. 82 : Desalination, or Power Production, or any Combination ThereofPowered by Power Generated from the use of at Least a Portion of LowDensity Fluid in Energy Storage System as a Fuel

FIG. 83 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 84 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 85 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 86 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 87 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 88 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 89 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 90 : An embodiment with subsea, underground lower elevationreservoir.

FIG. 91 : Energy Storage Charging, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 92 : Energy Storage Steady State, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 93 : Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, Desalination PressurizationPowered by Pressure Exchange with High Pressure Low Density Fluid fromDischarging Energy Storage System

FIG. 94 : Energy Storage Charging, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 95 : Energy Storage Steady State, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 96 : Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, High Pressure Low Density Fluidfrom Energy Storage Discharging may Comprise Pressurized DesalinationFeed Water and may Provide at Least a Portion of the Power forDesalination

FIG. 97 : Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, High Pressure Low Density Fluidfrom Energy Storage Discharging may Comprise Pressurized DesalinationFeed Water and may Provide at Least a Portion of the Power forDesalination, at Least a Portion of Power may be Extracted from HighPressure Low Density Fluid before being Employed as PressurizedDesalination Feed Water

FIG. 98 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is charging.

FIG. 99 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is at a steadystate.

FIG. 100 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is discharging,

FIG. 101 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is at a steadystate.

FIG. 102 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is charging.

FIG. 103 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is at a steadystate.

FIG. 104 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is discharging.

FIG. 105 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein the system is at a steadystate.

FIG. 106 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein high density fluid and lowdensity fluid are stored separately in the higher elevation reservoirand wherein the system is charging.

FIG. 107 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein high density fluid and lowdensity fluid are stored separately in the higher elevation reservoirand wherein the system is at a steady state.

FIG. 108 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein high density fluid and lowdensity fluid are stored separately in the higher elevation reservoirand wherein the system is discharging.

FIG. 109 : A system for storing or generating power by transferring lowdensity fluid and a high density fluid between a lower elevationreservoir and a higher elevation reservoir employing a lower elevationpump and/or power generation device wherein high density fluid and lowdensity fluid are stored separately in the higher elevation reservoirand wherein the system is at a steady state,

FIG. 110 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column,

FIG. 111 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 112 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 113 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 114 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 115 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 116 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 117 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 118 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 119 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 120 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 121 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 122 : A system or process for desalinating water wherein at least aportion of power is provided by the difference in gravitationalhydrostatic pressure between desalination feed and desalinated water dueto the difference in density between desalination feed and desalinatedwater and the elevation difference of a liquid column.

FIG. 123 : A system or process for generating power from thegravitational hydrostatic pressure difference between brine and seawaterdue to the difference in density between brine and seawater and thedifference in elevation of a liquid column.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 65-82 and FIGS. 91-97 Description

Some of the present embodiments may relate to systems and methods ofintegrated energy storage and desalination.

Some embodiments may involve employing the power from discharging anenergy storage system to power desalination. In some embodiments, thedischarging may be conducted in a manner which enables greater energyefficiency or greater round trip efficiency. In some embodiments, thedischarging may be conducted in a manner which enables greater energyefficiency or greater round trip efficiency than converting themechanical work or hydraulic pressure into electricity.

For example, some embodiments may comprise pressure exchanging the highpressure, low density fluid generated during discharging withdesalination feed water, which may pressurize the desalination feedwater to overcome the osmotic pressure of the desalination feed water,which may power at least a portion of the energy required fordesalination. For example, in reverse osmosis desalination, pressurizingthe desalination feed water to enable a pressure difference across adesalination membrane greater than the osmotic pressure of thedesalination feed water may comprise most of the energy consumption indesalination. Pressure exchanging may be more energy efficient thanconverting the hydraulic pressure or mechanical work into electricity,especially if said electricity may be otherwise further employed topower desalination. For example, some desalination pressure exchangersare 95-99.5% energy efficient, which may be generally more energyefficient than most systems and methods for converting mechanical workor hydraulic pressure into electricity. In some embodiments, thepressure exchange may enable the output pressure of the desalinationfeed water to be similar to or about the same as the input low densityfluid. In some embodiments, the pressure exchanger may enable the outputpressure of the desalination feed water to be less than the pressure ofthe input low density fluid. For example, in some embodiments, the inputlow density fluid may have a first pressure and a first flow rate andthe output desalination feed water may have a second pressure and asecond flow rate, wherein the first pressure is greater than the secondpressure and the second flow rate is greater than the first flow rate.In some embodiments, the pressure exchanger may enable the outputpressure of the desalination feed water to be less than the pressure ofthe input low density fluid. For example, in some embodiments, the inputlow density fluid may have a first pressure and a first flow rate andthe output desalination feed water may have a second pressure and asecond flow rate, wherein the first pressure is less than the secondpressure and the second flow rate is less than the first flow rate.

For example, some embodiments may involve the high pressure, low densityfluid comprising desalination feed water, or about the same compositionas desalination feed water, or any combination thereof. For example, thehigh pressure, low density fluid comprising desalination feed water maybe transferred into a desalination process. For example, the highpressure, low density fluid comprising desalination feed water may betransferred into a desalination process, wherein the desalination feedwater may already be sufficiently pressurized to overcome the osmoticpressure of the desalination feed water, which may result in desalinatedwater permeate. For example, by employing high pressure, low densityfluid comprising desalination feed water as the desalination feed water,the energy storage system may require less power transformations tosupply the desalination process with power for desalination, which mayresult in significantly greater round trip energy efficiency. Forexample, in some embodiments, if the high pressure, low density fluidcomprising desalination feed water is employed as desalination feedwater, the energy storage system may possess a round trip energyefficiency about equal to the efficiency of the pump required topressurize or pump the low density fluid during charging and anyfrictional losses in the pipes. Because the desalination system mayrequire pumps to pressurize the desalination feed regardless of theenergy storage system, the total practical or end-to-end round-tripenergy efficiency losses associated with the energy storage in thedesalination process may be negligible.

For example, in some embodiments, if the pump has an energy efficiencyof 92% and the pipe frictional losses are 1% on a total basis, theenergy storage system may have a round trip energy efficiency of 91%,however, factoring in that high pressure pumping would be requiredregardless in the desalination system, a round trip energy efficiency of99% may be more representative of the contextualized or end-to-end roundtrip energy efficiency of the example energy storage system.

For example, some embodiments may involve the high pressure, low densityfluid comprising desalination feed water, or about the same compositionas desalination feed water, or any combination thereof. For example, thehigh pressure, low density fluid comprising desalination feed water maybe transferred into a desalination process. For example, the highpressure, low density fluid comprising desalination feed water may betransferred into a desalination process, wherein the desalination feedwater may already be sufficiently pressurized to overcome the osmoticpressure of the desalination feed water, which may result in desalinatedwater permeate. In some embodiments, the pressure of the high pressurelow density fluid from the energy storage system may be significantlygreater than the pressure required for desalination. It may be desirableto first extract pressure or power from the high pressure low densityfluid to reduce the pressure of the low density fluid to a pressure moreoptimal for desalination and/or while productively using the extractedpressure or power. For example, some embodiments may involve extractingpressure or power from the high pressure low density fluid comprisingdesalination feed water using a pressure exchanger, wherein the pressureexchanger pressurizes additional desalination feed water fordesalination. For example, some embodiments may involve extractingpressure or power from the high pressure low density fluid comprisingdesalination feed water using a turbine or generator, which may convertthe extracted pressure or power into electricity.

Some embodiments may involve multiple options of energy inputs and valuestreams. For example, some embodiments may enable desalination to bepowered by electricity from one or more or any combination ofelectricity sources, or desalination to be powered by discharging theenergy storage system, or any combination thereof. For example, someembodiments may involve optionally discharging the energy storage systemto power the desalination of water, or generate electricity, or anycombination thereof. For example, in embodiments where the low densityfluid may comprise a potential fuel, it may be desirable under certaincircumstances to employ the low density fluid as an energy or powersource to, for example, including, but not limited to, one or more orany combination of the following: generate electricity, or desalinatewater, or power a chemical synthesis process, or as a feedstock in achemical synthesis process, or an intermediate in a chemical synthesisprocess, or a chemical in a chemical synthesis process, or a chemical ina chemical production process, or to produce heat, or any combinationthereof. Said certain circumstances may include, but are not limited to,one or more or any combination of the following: supply chain shortage,or supply chain disruption, or delivery delay, or high commodity prices,or high electricity prices, or electricity shortage, or brown out, orblack out, or natural disaster, or man-made disaster, or processdisruption, or process delay, or power outage, or earthquake, ortsunamic, or volcanic eruption, or hurricane, or flooding, or mudslide,or landslide, or pipeline leak, or militant attack, or explosion, ortornado, or drought, or long period of low wind speeds, or long periodof low sun, or commodity shortage.

Some embodiments may involve employing the same pump or pumps for energystorage as are employed for desalination. For example, some embodimentsmay comprise employing the pumps employed in energy storage in directlypumping desalination feed water for desalination, as in, for example,desalination feed water may flow through the same pumps. For example,some embodiments may comprise employing the pump or pumps employed inenergy storage to also indirectly pump for desalination, which mayinvolve, for example, pressurizing low density fluid in a circulatingloop, wherein the pressurized low density fluid may be pressureexchanged with desalination feed water, pressurizing and/or pumping thedesalination feed water.

Some embodiments may involve locating at least a portion of adesalination system subsea. In some embodiments, at least a portion of adesalination system may be located at or near the elevation of the lowerelevation reservoir. In some embodiments, at least a portion of adesalination system may be located at an elevation greater than theelevation of the lower elevation reservoir and lower than the elevationof the higher elevation reservoir. In some embodiments, it may bedesirable to locate. In some embodiments, it may be desirable topressure exchange the high pressure low density fluid with thedesalination feed water in a desalination system located at a mediumelevation. In some embodiments, it may be desirable to employ highpressure low density fluid comprising desalination feed water asdesalination feed water, during, for example, desalination. For example,it may be desirable to locate the desalination system at a mediumelevation comprising, for example, a water depth or subsea depth of 200meters-500 meters deep.

In some embodiments, it may be desirable to add low density fluidcomprising desalination feed water to the higher elevation reservoir to,for example, makeup for low density fluid comprising desalination feedwater exiting the energy storage system due to, for example, including,but not limited to, one or more or any combination of the following:being converted into desalinated water and/or desalination brine in adesalination process, or an overpressure event.

In some embodiments, desalination or the desalination process may occursubsea, however at least a portion of the pumping or pressurization ofthe desalination feed water may be powered by, or may be driven by, ormay occur by pumps or other devices located above or near the surface ofthe water. In some embodiments, desalination or the desalination processor the desalination membrane may be located subsea, however at least aportion of the pumping or pressurization of the desalination feed watermay be powered by, or may be driven by, or may occur by pumps or otherdevices located above or near the surface of the water.

Example FIGS. 65-82 and FIGS. 91-97 Key

Label Description Higher The ‘High Elevation’ label may be for thedashed line box which the ‘Higher Elevation Elevation’ text is insideand may represent the elevation of the system components in the dashedline box relative to system components in or between other dashed lineboxes. ‘High Elevation’ may comprise the higher elevation region. HighElevation may comprise an elevation higher than the elevation of theMedium Elevation and/or an elevation higher than the elevation of theLower Elevation. Medium The ‘Medium Elevation’ label may be for thedashed line box which the ‘Medium Elevation Elevation’ text is insideand may represent the elevation of the system components in the dashedline box relative to system components in or between other dashed lineboxes. ‘Medium Elevation’ may comprise a medium elevation region ormiddle elevation region. Medium Elevation may comprise an elevationhigher than the elevation of the Lower Elevation and/or an elevationlower than the elevation of the High Elevation. Lower The ‘LowerElevation’ label may be for the dashed line box which the ‘LowerElevation Elevation’ text is inside and may represent the elevation ofthe system components in the dashed line box relative to systemcomponents in or between other dashed line boxes. ‘Lower Elevation’ maycomprise a lower elevation region. Lower Elevation may comprise anelevation lower than the elevation of the Medium Elevation and/or anelevation lower than the elevation of the Higher Elevation. 1 ‘1’ maycomprise a high elevation reservoir or higher elevation storagereservoir. ‘1’ may comprise one or more storage units. For example, ‘1’may comprise one tank, or two tanks, or more tanks. ‘1’ may comprise atank configured to store high density fluid and low density fluid. ‘1’comprise a reservoir configured to store the low density fluid instorage units or storage tanks separate from the high density fluid. ‘1’may comprise a closed vessel. ‘1’ may comprise an open vessel. ‘1’ maycomprise a body of liquid. ‘1’ may comprise an open body of liquid. ‘1’may comprise an at least partially closed body of liquid. In someembodiments, the higher elevation reservoir may comprise a closedvessel, such, as a tank, or may comprise a contained reservoir, such asa lined pond. In some embodiments, the higher elevation reservoir maycomprise an open body of water, such as an ocean, or sea, or lake. 2 ‘2’may comprise low density fluid transferred between a higher elevationreservoir and a valve, or flow controller, or pump, or any combinationthereof. ‘2’ may comprise low pressure low density fluid. 3 ‘3’ maycomprise a valve, or flow controller, or pump, or any combinationthereof to direct or transfer low density fluid to or from a highelevation reservoir, or a pressure exchanger, or a pump, or a generator,or a turbine, or any combination thereof. 4 ‘4’ may comprise low densityfluid transferred between a valve, or flow controller, or pump, or anycombination thereof and a pump, or pressure exchanger, or turbine, orgenerator. ‘4’ may comprise low pressure low density fluid. 5 ‘5’ maycomprise a pump, or generator, or turbine. ‘5’ may be designed to pumplow density fluid. ‘5’ may be designed to generate power from thepotential or kinetic energy of low density fluid. ‘5’ may be designed toconvert power input, such as electricity, into mechanical energy orpotential energy, or may be designed to convert a power input intopumping or pressurizing of the low density fluid. 6 ‘6’ may comprisepower input or output. ‘6’ may comprise electricity input to power apump. ‘6’ may comprise electricity output from a generator, or turbine.7 ‘7’ may comprise low density fluid transferred between a pump, orturbine, or generator and a valve, or flow controller, or pump. ‘7’ maycomprise high pressure low density fluid. 8 ‘8’ may comprise a valve, orflow controller, or pump transferring low density fluid to or from apump or turbine or generator, or a higher elevation pressure exchanger,or a medium elevation pressure exchanger, or a lower elevation pressureexchanger, or a lower elevation reservoir, or any combination thereof. 9‘9’ may comprise ow density fluid transferred to or from a lowerelevation region, or medium elevation region, or a pressure exchanger,or a lower elevation reservoir, or any combination thereof. ‘9’ maycomprise high pressure low density fluid. ‘9’ may comprise a pipe orriser. 10 ‘10’ may comprise a pressure exchanger for, for example,pressure exchanging low density fluid and high density fluid. ‘10’ maycomprise a pressure exchanger located near or in the lower elevationregion. ‘10’ may comprise a pressure exchanger or power exchanger orsimilar process which may involve transferring power or pressure fromone fluid to another fluid. 11 ‘11’ may comprise low density fluidtransferred between a pressure exchanger and a lower elevation storagereservoir. 12 ‘12’ may comprise a lower elevation reservoir. ‘12’ maycomprise one or more storage units. For example, ‘12’ may comprise onetank, or two tanks, or more tanks. ‘12’ may comprise a tank configuredto store high density fluid and low density fluid. ‘12’ comprise areservoir configured to store the low density fluid in storage units orstorage tanks separate from the high density fluid. ‘12’ may comprise aclosed vessel. ‘12’ may comprise an open vessel. ‘122’ may comprise abody of liquid. ‘1’ may comprise an open body of liquid. ‘12’ maycomprise an at least partially closed body of liquid. In someembodiments, the higher elevation reservoir may comprise a closedvessel, such as a tank. 13 ‘13’ may comprise high density fluidtransferred between a pressure exchanger and a lower elevation storagereservoir. 14 ‘14’ may comprise high density fluid transferred between alower elevation region, or lower elevation reservoir, or lower elevationpressure exchanger, or any combination thereof and a higher elevationreservoir. 15 ‘15’ may comprise low density fluid transferred between avalve and a pressure exchanger. ‘15’ may comprise high pressure, lowdensity fluid before pressure exchanging with desalination feed water.16 ‘16’ may comprise a pressure exchanger or power exchanger or similarprocess which may involve transferring power or pressure from the highpressure low density fluid to the low pressure desalination feed water,which may result in high pressure desalination feed water and lowpressure low density fluid. 17 ‘17’ may comprise low density fluidtransferred between a pressure exchanger and a valve. ‘17’ may compriselower pressure low density fluid following a pressure exchange or powerexchange. 18 ‘18’ may comprise desalination feed water. ‘18’ maycomprise seawater, or brackish water, or the water or liquid orrequiring desalination. ‘18’ may comprise pre-treated or treatedseawater. 19 ‘19’ may comprise a valve, or pump, or flow controller, orany combination thereof which may transfer desalination feed water to apressure exchanger, or a desalination process, or any combinationthereof 20 ‘20’ may comprise desalination feed water transferred betweena valve, or pump, or flow controller, or any combination thereof and adesalination process, or valve or pump or flow controller, or anycombination thereof. ‘20’ may involve at least a portion of thedesalination feed water bypassing a pressure exchanger with highpressure low density fluid. For example, in some embodiments, at least aportion of desalination may be conducted using power or pressure fromanother source, such as, for example, electricity and/or electric pumps.For example, in some embodiments, when desired, at least a portion ofdesalination may be powered by electricity or other power source insteadof or in addition to pressure exchanging with the low density fluid. Forexample, in some embodiments, when the energy storage system ischarging, or when affordable electricity is available, or anycombination thereof, it may be desirable to power desalination usingelectricity, or electricity from a power source other than the energystorage system, or any combination thereof. 21 ‘21’ may comprisedesalination feed water transferred between a valve, or pump, or flowcontroller, or any combination thereof and a pressure exchanger. ‘21’may comprise low pressure desalination feed water. In some embodiments,it may be desirable for the desalination feed water to be directed thepathway of ‘21’ if the energy storage system is discharging, or if thepower for desalination or pressurization of the desalination feed watermay be from pressure exchange with the low density fluid, or anycombination thereof. For example, in some embodiments, the pump employedto pressurize low density fluid for charging the fluid displacementenergy storage system may also be employed to pressurize low densityfluid to power desalination by recirculating the low density fluid in aloop through the pressure exchanger. For example, in some embodiments,during discharging, power or pressure may be transferred from the lowdensity fluid to the desalination feed water or ‘21’. 22 ‘22’ maycomprise desalination feed water transferred from a pressure exchangerto a valve, or a pump, or a flow controller, or a desalination process,or a desalination membrane, or treatment step, or any combinationthereof. ‘22’ may comprise high pressure desalination feed water. 23‘23’ may comprise a valve, or flow controller, or pump, or anycombination thereof transferring desalination feed water from a pressureexchanger, or other desalination feed water source, or any combinationthereof to a desalination process, or reverse osmosis process, or anycombination thereof. In some embodiments, the desalination feed waterentering ‘23’ may comprise pressurized desalination feed water, ornon-pressurized desalination feed water, or any combination thereof. Insome embodiments, desalination feed water exiting ‘23’ may comprisepressurized desalination feed water, or non-pressurized desalinationfeed water, or any combination thereof. 24 ‘24’ may comprisedesalination feed water transferred from a valve, or flow controller, orpump, or any combination thereof to a desalination process. In someembodiments, ‘24’ may comprise pressurized desalination feed water ordesalination feed water at a pressure sufficiently high to overcome theosmotic pressure of the desalination feed water during a reverse osmosisor other pressure based desalination process. In some embodiments, ‘24’may comprise unpressurized desalination feed water or desalination feedwater at a pressure lower than the pressure required to overcome theosmotic pressure of the desalination feed water during a reverse osmosisor other pressure based desalination process. 25 ‘25’ may comprise adesalination process. ‘25’ may include, but is not limited to, one ormore or any combination of the following: reverse osmosis, orosmotically assisted reverse osmosis, or membrane desalination, ornanofiltration, or high pressure reverse osmosis, or high pressurenanofiltration. ‘25’ may involve pumps, or pressure exchangers, or powerrecovery, or energy recovery, or pre-treatment, or post-treatment, orstorage, or any combination thereof. 26 ‘26’ may comprise desalinationpermeate. ‘26’ may comprise a liquid or water with a lower salinity thanthe desalination feed water. ‘26’ may comprise potable water, orpractically freshwater, or freshwater according to municipal waterdefinitions, or freshwater according to industrial water definitions, orany combination thereof. ‘26’ may be transferred to storage, ortransport, or pipeline, or vehicle, or vessel, or application, ormunicipal water application, or industrial water application, or anycombination thereof. 27 ‘27’ may comprise desalination concentrate orretentate. ‘27’ may comprise a liquid or water with a greater salinitythan the desalination feed water. ‘27’ may be discharged, or released,or employed in an application, or may be further concentrated, or anycombination thereof. 28 ‘28’ may comprise an electricity or power input.‘28’ may comprise electricity input to power desalination or power thepressurization of desalination feed water instead of, or in addition to,pressurization of desalination feed water using a pressure exchange, orwherein the low density fluid during discharging of the energy storagesystem comprises pressurized low density fluid, or any combinationthereof. 29 ‘29’ may comprise low density fluid transferred from a lowerelevation reservoir, or pressurize exchanger, or higher elevation valve,or medium elevation valve, or any combination thereof to or toward adesalination process. ‘29’ may comprise low density fluid, wherein atleast a portion of said low density fluid comprises desalination feedwater. ‘29’ may comprise high pressure low density fluid, wherein thelow density fluid comprises at least a portion of desalination feedwater. 30 ‘30’ may comprise low density fluid, or desalination feedwater, or any combination thereof. ‘30’ may comprise desalination feedwater transferred to a storage reservoir, or a higher elevation storagereservoir, or any combination thereof. ‘30’ may comprise desalinationfeed water transferred to a storage reservoir, or a higher elevationstorage reservoir, or any combination thereof to, for example, makeupfor the volume or amount of high pressure low density fluid employed asdesalination feed water and/or converted into desalinated permeateand/or concentrate or retentate. 31 ‘31’ may comprise a low densityfluid, storage tank, or desalination feed water storage tank, or abuffer tank, or a transfer tank, or any combination thereof. In someembodiments, ‘31’ may be employed to enable the transfer of low densityfluid into the higher elevation storage reservoir with control, orsmooth transition. 32 ‘32’ may comprise low density fluid transferredinto the higher elevation reservoir. ‘32’ may comprise low density fluidtransferred into the higher elevation reservoir to make up for lowdensity fluid exiting the energy storage system to be employed asdesalination feed water. 33 ‘33’ may comprise desalination feed water.‘33’ may comprise low pressure desalination feed water input beingtransferred to a pump to be pressurized for desalination. In someembodiments, a pump employed during charging of the energy storagesystem may also be employed to pressurize desalination feed water fordesalination, even if the desalination feed water being pressurized anddirectly transferred to a desalination process, rather than beingemployed as a low density fluid in the energy storage systemintermediately. For example, when the energy storage system is fullycharged, or when the energy storage system is not charging, or when theenergy storage system is charging, or when the energy storage system isnot discharging, or when the energy storage system is discharging, orwhen electricity is available or affordable, or any combination thereof,it may be desirable to pressurize at least a portion of the desalinationfeed water using at least one of the same pumps employed for pumping orpressurizing low density fluid in the energy storage system. 34 ‘34’ maycomprise pressurized desalination feed water employed for or transferredto desalination or a desalination process. In some embodiments, ‘34’ maycomprise the same solution as ‘7’, or may comprise ‘7’ directed to adesalination process. 35 ‘35’ may comprise low density fluid transferredto or from a higher elevation storage reservoir. ‘35’ may comprise lowdensity fluid, which may comprise a fuel. For example, the low densityfluid may comprise, including, but not limited to, a hydrocarbon, orbutane, or propane, or diesel, or gasoline, or crude oil, or ethane, ormethane, or kerosene, or hydrogen, or ammonia, or any combinationthereof. ‘35’ may comprise low density fluid transferred to a powergeneration system or method, which may combust or otherwise convert thelow density fluid into power, or mechanical work, or electricity, or anycombination thereof. 36 ‘36’ may comprise a power generation system ormethod, which may comprise system or process for converting fuel, whichmay comprise low density fluid, into power, or mechanical work, orelectricity, or any combination thereof. ‘36’ may comprise, for example,including, but not limited to, one or more or any combination of thefollowing: a gas turbine, or a combustion engine, or a piston, or agenerator, or a steam turbine, or a Rankine cycle, or a stirring engine,or a fuel cell, or any combination thereof. It may be desirable toemploy ‘36’ as a backup or emergency source of power, for example, incase electricity is unavailable, or electricity is too expensive, orother power source is unavailable, or other power source is tooexpensive, or the other power sources are more expensive, or the energystorage system is fully discharged, or the energy storage system isbeing maintained, or the energy storage system is out of service, or anycombination thereof. 37 ‘37’ may comprise electricity, or mechanicalfluid, or hydraulic fluid, or pneumatic fluid, or power, or other formof power transfer medium. ‘37’ may comprise power generated from thepower generation system or method, which may comprise ‘36’. ‘37’ maycomprise power transferred to a desalination process to power thedesalination process. ‘37’ may comprise power transferred to anelectricity grid or other power consuming application. 38 ‘38’ maycomprise high pressure low density fluid. ‘38’ may comprise highpressure low density fluid transferred in a medium elevation region.‘38’ may comprise low density fluid, or high pressure low density fluid,or any combination thereof transferred to a desalination process. ‘38’may comprise low density fluid, or high pressure low density fluid, orany combination thereof transferred to a power extraction device, or apower extractor, or turbine, or generator, which may generate power fromthe high pressure low density fluid. 39 ‘39’ may comprise a powerextraction device, or a power extractor, or turbine, or generator, whichmay generate power from the high pressure low density fluid, and/or mayreduce the pressure of the low density fluid to a pressure greater thanthe osmotic pressure of the desalination feed water, or to a pressuregreater than the hydrostatic pressure at the water depth by an amountequal to or greater than the osmotic pressure of the desalination feedwater, or to a pressure desired for the desalination process, or anycombination thereof. 40 ‘40’ may comprise a low density fluid comprisingdesalination feed water at a pressure desired for a desalinationprocess. 42 ‘42’ may comprise electricity, or mechanic power, orhydraulic power, or other form of power extracted or otherwise producedfrom the high pressure low density fluid. Power in ‘42’ may betransferred to an application requiring or otherwise benefiting from orneeding said power.

Example FIGS. 65-82 and FIGS. 91-97 Step-by-Step Descriptions

FIG. 65 Energy Storage Charging, Desalination Powered by External Source

Energy Storage:

Low density fluid from a higher elevation reservoir may be pumped usinga pump to a lower elevation region. Low density fluid exiting the pumpmay be at a pressure greater than or equal to the hydrostatic orgravitational pressure of the high density fluid in the elevationdifference between the higher elevation reservoir and lower elevationreservoir minus the hydrostatic or gravitation pressure of the lowdensity fluid in the elevation difference between the higher elevationreservoir and lower elevation reservoir.

In the lower elevation region, the high pressure low density fluid maypressure exchange with the high density fluid in the lower elevationregion, which may result in transfer of high density fluid from thelower elevation reservoir through the lower elevation pressure exchangerand into the higher elevation reservoir, and/or the transfer of lowdensity fluid into the lower elevation reservoir.

Note: Adding a high density fluid to a reservoir, wherein the additionof the high density fluid into the reservoir, or the process oftransferring the high density fluid to the reservoir, or the process oftransferring the high density fluid between reservoirs, or anycombination thereof results in removal or exiting of low density fluidfrom said reservoir may comprising ‘displacing’ low density fluid or‘displacement’ of low density fluid.

Note: Adding a low density fluid to a reservoir, wherein the addition ofthe low density fluid into the reservoir, or the process of transferringthe low density fluid to the reservoir, or the process of transferringthe low density fluid between reservoirs, or any combination thereofresults in removal or exiting of high density fluid from said reservoirmay comprising ‘displacing’ high density fluid or ‘displacement’ of highdensity fluid.

Desalination:

Desalination feed water may be transferred into a desalination process,where it may be pressurized and converted into desalinated waterpermeate and desalination retentate or concentrate. In some embodiments,the desalination may be capable of operating with pumps, or powersources, or any combination thereof external from or separate from theenergy storage system if desired, or when desired, or any combinationthereof.

FIG. 66 Energy Storage Steady State, Desalination Powered by ExternalSource

Desalination:

Desalination feed water may be transferred into a desalination process,where it may be pressurized and converted into desalinated waterpermeate and desalination retentate or concentrate. In some embodiments,the desalination may be capable of operating with pumps, or powersources, or any combination thereof external from or separate from orindependently of the energy storage system if desired, or when desired,or any combination thereof.

FIG. 67 Energy Storage Discharging, Desalination Powered by PressureExchange with High Pressure Low Density Fluid Produced by DischargingEnergy Storage System

Energy Storage:

High Density Fluid may be transferred from the higher elevationreservoir to the lower elevation region.

In the lower elevation region, the high density fluid may be pressureexchanged with the low density fluid in the lower elevation region,which may result in transfer of low density fluid from the lowerelevation reservoir through the lower elevation pressure exchanger andinto the higher elevation region and/or the transfer of high densityfluid into the lower elevation reservoir.

In the higher elevation region, the low density fluid transferred fromthe lower elevation region, which may comprise high pressure low densityfluid, may be pressure exchanged with desalination feed water, whereinat least a portion of the power or pressure in the high pressure lowdensity fluid is transferred to the desalination feed water. In someembodiments, the resulting pressure of the desalination feed water afterpressure exchange may be greater than the osmotic pressure of thedesalination feed water, which may enable the desalination of thedesalination feed water and/or enable the powering at least a portion ofdesalination by pressure exchanging the high pressure low density fluidwith desalination feed water during the discharging of the energystorage system. After pressure exchange with desalination feed waterand/or further power extraction, the low density fluid may betransferred into the higher elevation reservoir.

Desalination:

Low pressure desalination feed water may be transferred into a pressureexchanger, where it may be pressure exchanged with the high pressure lowdensity fluid, which may result in pressurized desalination feed waterand low pressure low density fluid. The pressurized desalination feedwater may be transferred into a pressure driven desalination process,such as a reverse osmosis process, wherein the pressurized desalinationfeed water may be converted into desalination permeate and concentrateor retentate. The pressurization of the desalination feed water bypressure exchange may power the pressurization energy requirement ofdesalination, which may comprise a significant proportion of the totalenergy consumption related to desalination.

FIG. 68 Energy Storage Steady State, Desalination Powered by PressureExchange with Recirculating Low Density Fluid

Desalination:

Low density fluid in the energy storage process may power the pumping orpressurization of desalination feed water by recirculatingpressurization of the low density fluid and pressure exchange with thedesalination feed water. For example, low pressure low density fluid maybe transferred into a pump, where it may be pressurized into relativelyhigh pressure low density fluid. Said high pressure low density fluidmay be transferred to a pressure exchanger, which may pressure exchangethe high pressure low density fluid with low pressure desalination feedwater, which may result in pressurized desalination feed water and lowpressure low density fluid. The low pressure density fluid may betransferred to the pump. The pressurized desalination feed water may betransferred into a desalination process, such as a pressure drivendesalination process, such as reverse osmosis, wherein the pressurizeddesalination feed water may be converted into desalination permeate anddesalination concentrate or retentate. The present embodiment may bebeneficial or desirable because it may enable desalination to be poweredusing the same equipment, such as pumps or pressure exchangers, as maybe used by the energy storage system during charging and discharging,even when the energy storage system may be at a steady state, which mayreduce capital cost and weight of equipment.

FIG. 69 Energy Storage Charging, Desalination May be Powered by PressureExchange a Portion of High Pressure Low Density Fluid Produced by EnergyStorage System Charging, a Portion of Low Density Fluid May beRecirculated

Energy Storage:

Low density fluid from a higher elevation reservoir may be pumped usinga pump. A portion of the high pressure low density fluid from saidpumping may be transferred to a lower elevation region. A portion of thehigh pressure low density fluid from said pumping may be transferred toa pressure exchanger with the desalination feed water, which may belocated in the higher elevation region, or medium elevation region, orany combination thereof. Low density fluid exiting the pump transferredto the lower elevation region may be at a pressure greater than or equalto the hydrostatic or gravitational pressure of the high density fluidin the elevation difference between the higher elevation reservoir andlower elevation reservoir minus the hydrostatic or gravitation pressureof the low density fluid in the elevation difference between the higherelevation reservoir and lower elevation reservoir.

In the lower elevation region, the high pressure low density fluid maypressure exchange with the high density fluid in the lower elevationregion, which may result in transfer of high density fluid from thelower elevation reservoir through the lower elevation pressure exchangerand into the higher elevation reservoir, and/or the transfer of lowdensity fluid into the lower elevation reservoir.

The high pressure low density fluid transferred to a pressure exchangerwith the desalination feed water may be pressure exchanged withdesalination feed water, which may result in pressurized desalinationfeed water and low pressure low density fluid. Low pressure low densityfluid may be recirculated to the pump, or may be transferred to thehigher elevation reservoir, or any combination thereof. The pressurizeddesalination feed water may be transferred to a desalination process.

Desalination:

Low density fluid in the energy storage process may power the pumping orpressurization of desalination feed water by recirculatingpressurization of the low density fluid and pressure exchange with thedesalination feed water. For example, low pressure low density fluid maybe transferred into a pump, where it may be pressurized into relativelyhigh pressure low density fluid. A portion of said high pressure lowdensity fluid may be transferred to a pressure exchanger, which maypressure exchange the high pressure low density fluid with low pressuredesalination feed water, which may result in pressurized desalinationfeed water and low pressure low density fluid. The low pressure densityfluid may be transferred to the pump. The pressurized desalination feedwater may be transferred into a desalination process, such as a pressuredriven desalination process, such as reverse osmosis, wherein thepressurized desalination feed water may be converted into desalinationpermeate and desalination concentrate or retentate. The presentembodiment may be beneficial or desirable because it may enabledesalination to be powered using the same equipment, such as pumps orpressure exchangers, as may be used by the energy storage system duringcharging and discharging.

FIG. 70 Energy Storage Discharging. Splitting High Pressure Low DensityFluid Stream to Power Simultaneous Electricity Generation andDesalination

Energy Storage:

High Density Fluid may be transferred from the higher elevationreservoir to the lower elevation region.

In the lower elevation region, the high density fluid may be pressureexchanged with the low density fluid in the lower elevation region,which may result in transfer of low density fluid from the lowerelevation reservoir through the lower elevation pressure exchanger andinto the higher elevation region and/or the transfer of high densityfluid into the lower elevation reservoir.

In the higher elevation region, the low density fluid transferred fromthe lower elevation region, which may comprise high pressure low densityfluid, may be split into at least two fluid streams, which may comprisea first fluid stream and a second fluid stream, wherein at least a firstfluid stream may be transferred to a generator or turbine to generatepower, such as electricity, and/or wherein at least a second fluidstream may be transferred to a pressure exchange with desalination feedwater to power at least a portion of the pressurization of desalinationfeed water for desalination. After generating power, the low densityfluid may be transferred into the higher elevation reservoir. Afterpressure exchanging with desalination feed water, the low density fluidmay be transferred into the higher elevation reservoir.

Desalination:

Low pressure desalination feed water may be transferred into a pressureexchanger, where it may be pressure exchanged with the high pressure lowdensity fluid, which may result in pressurized desalination feed waterand low pressure low density fluid. The pressurized desalination feedwater may be transferred into a pressure driven desalination process,such as a reverse osmosis process, wherein the pressurized desalinationfeed water may be converted into desalination permeate and concentrateor retentate. The pressurization of the desalination feed water bypressure exchange may power the pressurization energy requirement ofdesalination, which may comprise a significant proportion of the totalenergy consumption related to desalination.

FIG. 71 Energy Storage Charging, Desalinating Water with External PowerSource, Embodiment with Direct Fluid Displacement in Lower ElevationReservoir

Energy Storage:

Low density fluid from a higher elevation reservoir may be pumped usinga pump to a lower elevation region. Low density fluid exiting the pumpmay be at a pressure greater than or equal to the hydrostatic orgravitational pressure of the high density fluid in the elevationdifference between the higher elevation reservoir and lower elevationreservoir minus the hydrostatic or gravitation pressure of the lowdensity fluid in the elevation difference between the higher elevationreservoir and lower elevation reservoir.

In the lower elevation region, the high pressure low density fluid maybe transferred into the lower elevation reservoir, which may displace atleast a portion of the high density fluid in the lower elevation region,which may result in transfer of high density fluid from the lowerelevation reservoir to the higher elevation reservoir, and/or thetransfer of low density fluid into the lower elevation reservoir.

Desalination:

Desalination feed water may be transferred into a desalination process,where it may be pressurized and converted into desalinated waterpermeate and desalination retentate or concentrate. In some embodiments,the desalination may be capable of operating with pumps, or powersources, or any combination thereof external from or separate from theenergy storage system if desired, or when desired, or any combinationthereof.

FIG. 72 Energy Storage Charging, Desalinating Water with External PowerSource with Separate Pump from Energy Storage Pump

FIG. 73 Energy Storage Charging, Desalinating Water with Same Pump asEmployed in Energy Storage or Same Fluid as Low Density Fluid Employedin Energy Storage or any Combination Thereof

Energy Storage:

Low pressure low density fluid comprising desalination feed water and/oradditional low pressure desalination feed water may be transferred intoa pump, which may result in high pressure low density fluid comprisingdesalination feed water. The high pressure low density fluid may besplit into two fluid streams, which may comprise a first fluid streamand a second fluid stream, wherein the first fluid stream may betransferred to a lower elevation region and wherein the second fluidstream may be transferred to a desalination process.

Said first fluid stream comprising high pressure low density fluidtransferred to a lower elevation region may be pressure exchanged in thelower elevation region with high density fluid in the lower elevationregion, which may result in transfer of high density fluid from thelower elevation reservoir through the lower elevation pressure exchangerand into the higher elevation reservoir, and/or the transfer of the lowdensity fluid into the lower elevation reservoir.

Said second fluid stream comprising high pressure low density fluid maycomprise desalination feed water and may be transferred into adesalination process, wherein the pressure of the high pressure lowdensity fluid stream may power at least a portion of the desalination ofthe desalination feed water. In some embodiments, additional power orpressure may be extracted from the high pressure low density fluidstream before being employed as desalination feed water, if, forexample, the pressure of the high pressure low density fluid stream maybe significantly greater than the pressure required or desired fordesalination. In some embodiments, additional power or pressure may beadded to the high pressure low density fluid stream before beingemployed as desalination feed water, if, for example, the pressure ofthe high pressure low density fluid stream may be less than the pressurerequired or desired for desalination.

Desalination:

The second fluid stream comprising high pressure low density fluidcomprising desalination feed water may be transferred into adesalination process. The desalination process may employ the power orpressure of the higher pressure low density fluid stream comprisingdesalinated feed water to desalinate at least a portion of the water, orto reduce the energy consumption related to desalinating at least aportion of said desalinated feed water.

FIG. 74 Energy Storage Steady State, Desalinating Water with ExternalPower Source

FIG. 75 Energy Storage Steady State, Pressurizing Desalination FeedWater Using Same Pump as is Employed in Energy Storage

FIG. 76 Energy Storage Discharging, High Pressure Low Density Fluid fromDischarging Employed as at Least a Portion of Pressurized DesalinationFeed Water

High Density Fluid may be transferred from the higher elevationreservoir to the lower elevation region.

In the lower elevation region, the high density fluid may be pressureexchanged with the low density fluid in the lower elevation region,which may result in transfer of low density fluid from the lowerelevation reservoir through the lower elevation pressure exchanger andinto the higher elevation region and/or the transfer of high densityfluid into the lower elevation reservoir.

In the higher elevation region, the low density fluid transferred fromthe lower elevation region, which may comprise high pressure low densityfluid, and may comprise desalination feed water, may be transferred intoa desalination process as pressurized desalination feed water, which mayresult in the production of desalinated water.

Note: Low density fluid, which may comprise desalination feed water, maybe added to the energy storage system, or the higher elevationreservoir, or any combination thereof to, for example, one or more orany combination of the following: smake up for any low density fluidexiting the system, due to, for example, use in desalination, or due toanother application, or due to losses, or due to pressure release, orany combination thereof.

FIG. 77 Energy Storage Discharging, High Pressure Low Density Fluid fromDischarging Employed as at Least a Portion of Pressurized DesalinationFeed Water

FIG. 78 Energy Storage Discharging, High Pressure Low Density Fluid fromDischarging Wherein a Portion is Employed as Pressurized DesalinationFeed Water and a Portion is Employed for Power Generation

FIG. 79 Energy Storage Discharging, High Pressure Low Density Fluid fromDischarging Employed as at Least a Portion of Pressurized DesalinationFeed Water and for Power Generation

FIG. 80 Energy Storage Charging, Desalinating Water with External PowerSource, Embodiment May Comprise Direct Fluid Displacement in LowerElevation Reservoir

FIG. 81 Energy Storage Charging, Desalinating Water with Same PumpEmployed in Energy Storage, or a Portion of the High Pressure LowDensity Fluid Comprising Desalination Feed Water, or any CombinationThereof, Embodiment May Comprise Direct Fluid Displacement in LowerElevation Reservoir

FIG. 82 Desalination, or Power Production, or any Combination ThereofPowered by Power Generated from the Use of at Least a Portion of LowDensity Fluid in Energy Storage System as a Fuel

If desired, a portion of low density fluid may be transferred from theenergy storage system. For example, a portion of low density fluid maybe transferred from the higher elevation reservoir. In some embodiments,the low density fluid may comprise a chemical which contains chemicalenergy or may comprise a chemical which is combustible. For example, thelow density fluid may comprise, including, but not limited to, one ormore or any combination of the following: a hydrocarbon, or LPG, orbutane, or propane, or kerosene, or diesel, or gasoline, or ammonia, orhydrogen, or methanol, or ethanol, or propanol. In some embodiments, thelow density fluid may be transferred to process which generates powerfrom the low density fluid, such as, for example, a gas turbine, or agenerator, or an engine. Said process may generate power, which maycomprise, for example, electricity, or mechanical power, or hydraulicpower, or pneumatic power, or any combination thereof:

In some embodiments, said power may be transferred to an applicationrequiring or otherwise benefiting from said power. For example, in someembodiments, said power may be transferred to a desalination process topower at least a portion of desalination.

Note: When convenient or desired, low density fluid may be added to theenergy storage system or the higher elevation reservoir to make up forlow density fluid consumed for power generation.

FIG. 91 Energy Storage Charging, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 92 Energy Storage Steady State, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 93 Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, Desalination PressurizationPowered by Pressure Exchange with High Pressure Low Density Fluid fromDischarging Energy Storage System

FIG. 94 Energy Storage Charging, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 95 Energy Storage Steady State, Desalination occurring at MediumElevation or Subsea at Medium Elevation

FIG. 96 Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, High Pressure Low Density Fluidfrom Energy Storage Discharging may Comprise Pressurized DesalinationFeed Water and may Provide at Least a Portion of the Power forDesalination

FIG. 97 Energy Storage Discharging, Desalination occurring at MediumElevation or Subsea at Medium Elevation, High Pressure Low Density Fluidfrom Energy Storage Discharging may Comprise Pressurized DesalinationFeed Water and may Provide at Least a Portion of the Power forDesalination, at Least a Portion of Power may be Extracted from HighPressure Low Density Fluid before being Employed as PressurizedDesalination Feed Water

Note: in some embodiments, ‘steady state’ may mean the energy storagesystem is neither charging or discharging. In some embodiments, ‘steadystate’ may mean the energy storage system is remaining at a stable orconstant state of charge.

Note: ‘State of charge’ may comprise represent the amount of energystored in an energy storage system relative to the system's total energystorage capacity.

Note: In some embodiments, treated seawater (which may be from a bufferor reserve tank) may be added to the higher elevation reservoir to makeup for the loss of low density fluid, or high density fluid, or anycombination thereof employed as the desalination feed water.

Note: In some embodiments, air or other gas may be employed totemporarily occupy the volume of the tank previously occupied by lowdensity fluid, or high density fluid, or any combination thereofemployed as desalination feed water.

Note: A power recovery device may comprise any device which transferspower or converts power. In some embodiments, ‘pressure exchanger’ mayrefer to a ‘power recovery device’ and/or the terms ‘pressure exchanger’and ‘power recovery device’ or ‘energy recovery device’ may be employedinterchangeably. For example, a power recovery device may comprise,including, but not limited, one or more or any combination of thefollowing: a pressure exchanger, or a generator, or a turbine, or aturbocharger, or an electric generator.

Note: Desalination feed water may be sourced from a water depth deeperthan or equal to one or more or any combination of the following: 1meter, or 5 meters, or 10 meters, or 20 meters, or 30 meters, or 40meters, or 50 meters, or 60 meters, or 70 meters, or 80 meters, or 90meters, or 010 meters, or 150 meters, or 200 meters, or 250 meters, or300 meters, or 350 meters, or 400 meters, or 450 meters, or 500 meters,or 550 meters, or 600 meters, or 650 meters, or 700 meters, or 750meters, or 800 meters, or 850 meters, or 900 meters, or 950 meters, or1,000 meters, or 1,500 meters, or 2,000 meters, or 2,500 meters, or3,000 meters, or 3,500 meters, or 4,000 meters, or 4,500 meters, or5,000 meters. In some embodiments, sourcing desalination feed waterfurther from shore, or in deeper water, or any combination thereof mayresult in less particulates or pre-treatment requirement.

Note: Desalination retentate or concentrate may be released into aregion of a water body with a depth deeper than or equal to one or moreor any combination of the following: 1 meter, or 5 meters, or 10 meters,or 20 meters, or 30 meters, or 40 meters, or 50 meters, or 60 meters, or70 meters, or 80 meters, or 90 meters, or 010 meters, or 150 meters, or200 meters, or 250 meters, or 300 meters, or 350 meters, or 400 meters,or 450 meters, or 500 meters, or 550 meters, or 600 meters, or 650meters, or 700 meters, or 750 meters, or 800 meters, or 850 meters, or900 meters, or 950 meters, or 1,000 meters, or 1,500 meters, or 2,000meters, or 2,500 meters, or 3,000 meters, or 3,500 meters, or 4,000meters, or 4,500 meters, or 5,000 meters. In some embodiments, releasingdesalination retentate or concentrate further from shore, or in deeperwater, or any combination thereof may result in less impact on marinelife, or local marine chemistry, or marine ecosystems, or sea life, orecosystems.

Example Exemplary Embodiments

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto exit the second reservoir; and

wherein the first fluid is a liquid.

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto exit the second reservoir enter a hydraulic turbine or generator; and

wherein the first fluid is a liquid.

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto exit the second reservoir enter an energy recovery device or apressure exchanger; and

wherein the first fluid is a liquid.

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto exit the second reservoir enter a desalination process as the feedsolution; and

wherein the first fluid is a liquid; and

wherein the first fluid comprises treated seawater.

Wherein the first fluid exiting the second storage reservoir istransferred into a power recovery device

Wherein said power recovery device comprises a pressure exchanger

Wherein said power recovery device transfers the kinetic energy from thefirst fluid to a desalination feed stream

Wherein said power recovery device extracts power from the first fluidto pressurize desalination feed into a reverse osmosis process

Wherein said desalination feed comprises treated seawater

Wherein the first fluid is transferred into said first storage reservoirafter said power recovery

[Capable of Converting to Electricity or Pressurized Desalination Feed]

[Capable of Converting to Electricity or Pressurized Desalination Feedand Adjusting the Proportion Converted to Electricity or DesalinationFeed Depending on Demand]

Wherein the first fluid exiting the second storage reservoir comprises ahigh-pressure fluid with a pressure greater than the osmotic pressure ofseawater

Wherein the first fluid exiting the second storage reservoir istransferred to a desalination process, wherein at least a portion of thefirst fluid comprises the desalination feed

Wherein the first fluid exiting the second storage reservoir istransferred to a semipermeable membrane

Wherein the first fluid exiting the second storage reservoir istransferred into a desalination process, wherein the first fluid isseparated into desalinated water and desalination brine

Wherein the first fluid exiting the second storage reservoir istransferred into a desalination process, wherein the first fluid isseparated into desalinated water permeate and desalination retentateusing a semipermeable membrane

Wherein the first fluid exiting the second storage reservoir istransferred into a desalination process, wherein the first fluid isseparated into desalinated water permeate and desalination retentateusing a semipermeable membrane, and wherein the desalination retentateis discharged into the water body

Wherein treated seawater is added to the first storage reservoir tomakeup for the first fluid comprising treated seawater converted intodesalinated water in the desalination process

Wherein the low density fluid may comprise a fuel which may be burned topower desalination

Wherein the low density fluid may comprise a chemical synthesized fromthe desalinated water

Wherein the low density fluid may comprise a chemical synthesizedemploying the stored power

Wherein the low density fluid may comprise a synthesized chemical

Wherein the low density fluid may comprise desalinated water

Wherein the low density fluid may comprise seawater or treated seawater

Wherein the desalinated water may be converted to hydrogen

Wherein the desalinated water may be converted to oxygen

Wherein the desalinated water may be converted into chemicals

Wherein the desalinated water is transported to an application using apipeline or risers

Wherein the desalinated water is transported to an application onshore

Wherein the desalinated water is transported to an application offshore

Wherein the desalinated water is transferred using a ship or a mobilevessel

Wherein the desalinated water is transferred using a flying vessel

Wherein the desalinated water is transferred using a submarine or subseavessel or structure

Wherein the desalinated water is transferred using a flying vehicle

Wherein the synthesized chemicals are transferred using a pipeline

Wherein the synthesized chemicals are transferred using a ship orfloating vessel

Wherein the synthesized chemicals are transferred using a flying vehicle

Wherein the synthesized chemicals are transferred using a submarine orsubsea vessel or structure

Wherein the first storage reservoir is floating

Wherein the first storage reservoir is underwater

Wherein the first storage reservoir is on land

Wherein storing power by pumping a low density fluid to displace a highdensity fluid

Wherein stored power is employed to desalinate water

Wherein stored power is employed to desalinate water by pressureexchanging the low density fluid with feed seawater to pressurize thefeed seawater; and

Transferring said feed seawater to a reverse osmosis desalination system

Wherein stored power is employed to desalinate water by pressureexchanging the low density fluid with feed seawater to pressurize thefeed seawater; and

Contacting said feed seawater with a desalination membrane

Wherein stored power is employed to desalinate water by pressureexchanging the low density fluid with feed seawater to pressurize thefeed seawater: and

Contacting said feed seawater with a reverse osmosis membrane

Wherein stored power is employed to desalinate water by pressureexchanging the low density fluid with feed seawater to pressurize thefeed seawater; and

Contacting said feed seawater with a semipermeable membrane

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump;

wherein the pump and the first and second reservoir are operativelyconnected such that power is stored by displacing the second fluid whichhas a higher density than the first fluid in the second storagereservoir by pumping the first fluid in the first storage reservoir tothe second storage reservoir and power is generated by allowing thefirst fluid in the second storage reservoir to exit the secondreservoir; and

wherein the first fluid is a liquid.

(2) The system of example exemplary embodiment 1 wherein power isgenerated by transferring the first fluid into a power recovery device

(3) The system of example exemplary embodiment 2 wherein said powerrecovery device comprises a pressure exchanger

(4) The system of example exemplary embodiment 2 wherein said powerrecovery device transfers the power from the first fluid to adesalination feed stream

(5) The system of example exemplary embodiment 2 wherein said powerrecovery device extracts power from the first fluid to pressurizedesalination feed water

(6) The system of example exemplary embodiment 5 wherein saiddesalination feed water comprises seawater or treated seawater

(7) The system of example exemplary embodiment 5 wherein saidpressurized desalination feed water is transferred into a reverseosmosis desalination process

(8) The system of example exemplary embodiment 2 wherein the first fluidis transferred into the first storage reservoir after said powerrecovery

(9) The system of example exemplary embodiment 1 wherein the first fluidcomprises a chemical selected from the following: hydrocarbon, butane,propane, LPG, water, ammonia, ethanol, methanol, kerosene

(10) The system of example exemplary embodiment 1 wherein power in thefirst fluid is employed to generate electricity and pressure exchange topressurized desalination feed water

(11) The system of example exemplary embodiment 10 wherein theproportion of power converted into electricity relative to theproportion of power transferred in a pressure exchange to pressurizeddesalination feed water is adjustable

(12) The system of example exemplary embodiment 2 wherein the firstfluid transferred into a pressure recovery device comprises a pressuregreater than the osmotic pressure of the desalination feed water

(13) The system of example exemplary embodiment 1 wherein the firstfluid comprises desalination feed water

(14) The system of example exemplary embodiment 13 wherein power isgenerated by transferring the low density fluid into a desalinationprocess

(15) The system of example exemplary embodiment 14 wherein the firstfluid transferred to a desalination process comprises a pressure greaterthan the osmotic pressure of the desalination feed water

(16) The system of example exemplary embodiment 13 wherein at least aportion of the power in the first fluid is recovered using a powerrecovery device before transferring into a desalination process

(17) The system of example exemplary embodiment 13 wherein at least aportion of first fluid is transferred to an electric generator and atleast a portion of the first fluid is transferred to a desalinationprocess,

Wherein the electric generator generates electricity from at least aportion of the power in the first fluid, and

Wherein the desalination process converts at least a portion of thepower in the first fluid into desalinated water

(18) The system of example exemplary embodiment 17 wherein theproportion of first fluid transferred to the desalination process andthe proportion of first fluid transferred to the electric generator isadjustable

(19) The system of example exemplary embodiment 17 wherein theproportion of power in the first fluid transferred to the desalinationprocess and the proportion of power in the first fluid transferred tothe electric generator is adjustable

(20) The system of example exemplary embodiment 13 wherein the firstfluid exiting the second storage reservoir is transferred into adesalination process, wherein the first fluid is separated intodesalinated water

(21) The system of example exemplary embodiment 20 wherein desalinationfeed water is added to the first storage reservoir to make up for thefirst fluid exiting the system due to conversion into desalinated water

(22) The system of example exemplary embodiment 13 the first fluidexiting the second storage reservoir is transferred into a desalinationprocess, wherein the first fluid is separated into desalinated waterpermeate and desalination retentate using a semipermeable membrane, andwherein the desalination retentate is discharged into the water body

(23) The system of example exemplary embodiment 1 wherein the lowdensity fluid comprises desalinated water

(24) The system of example exemplary embodiment 1 wherein the storedpower is employed to desalinate water

(25) The system of example exemplary embodiment 24 wherein thedesalinated water is converted into chemicals selected from thefollowing: hydrogen, oxygen, synthetic fuels, fuels, ammonia, hydrogenderived chemicals, carbon dioxide derived chemicals, air derivedchemicals

(26) The system of example exemplary embodiment 1 wherein the higherelevation reservoir is in a location selected from the following: onland, floating on water, underwater

(27) The system of example exemplary embodiment 24 wherein thedesalinated water is transported by a method selected from thefollowing: a pipeline, a riser, a ship, an aircraft, a train, a truck, aconveyor belt

(28) The process of example exemplary embodiment 1 wherein the pump isemployed to pressurize desalination feed water for desalination

(29) A process for storing power and desalinating water comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump;

wherein the pump and the first and second reservoir are operativelyconnected such that power is stored by displacing the second fluid whichhas a higher density than the first fluid in the second storagereservoir by pumping the first fluid in the first storage reservoir tothe second storage reservoir; and

power is generated by allowing the first fluid to exit the secondstorage reservoir and pressure exchange with desalination feed water

(30) A process for storing power and desalinating water comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump;

wherein the pump and the first and second reservoir are operativelyconnected such that power is stored by displacing the second fluid whichhas a higher density than the first fluid in the second storagereservoir by pumping the first fluid in the first storage reservoir tothe second storage reservoir: and

power is generated by allowing the first fluid to exit the secondstorage reservoir and enter a desalination process;

wherein the first fluid comprises desalination feed water

Notes

Some embodiments may involve locating a desalination system ordesalination plant offshore. For example, some embodiments may involvelocating the desalination plant greater than 1 mile, or greater than 2miles, or 3 miles, or 4 miles, or 5 miles, or 10 miles, or 15 miles, or20 miles, or any combination thereof from shore. For example, someembodiments may involve locating the desalination plant on a floatingplatform, or floating vessel, or moored vessel, or semi-submersiblevessel, or any combination thereof. For example, some embodiments mayinvolve locating the desalination plant above water, or on the surfaceof a water body, or below the surface of a water body, or anycombination thereof. For example, some embodiments may involve locatingthe desalination plant on a vessel or platform in deep water, such as ina location where the water depth is greater than 100 meters, or greaterthan 150 meters, or greater than 200 meters, or greater than 500 meters,or greater than 1,000 meters, or any combination thereof. There may beone or more or a combination of benefits in locating a desalinationplant offshore, which may include, but are not limited to, one or moreor a combination of the following:

For example, by locating a desalination plant offshore, a desalinationplant may not occupy land, or may occupy substantially less land, orboth.

For example an offshore desalination plant may enable the desalinationin locations with limited available coastal land, or expensive coastland, or strict coastal zoning.

For example, an offshore desalination plant may substantially lower landor location costs because of minimal or no land use.

For example, an offshore desalination plant may require substantiallyless permitting or simpler permitting, or lower cost permitting, or anycombination thereof due to, for example, including, but not limited to,one or more or a combination of the following: minimal or nomodification to land, or minimal or no modification to coastal habitat,or minimal or no noise pollution, or minimal or no impact on roadvehicle traffic patterns, or minimal or no visual pollution, or minimalimpact to water access, or minimal or no impact to beach access, orminimal or no impact to coastal recreational activities.

For example, by locating a desalination plant offshore, the desalinationplant may have minimal constraints related to scale or capacity becausethe desalination plant may not be constrained by land use or landavailability. For example, larger capacity desalination plants may befeasibly constructed offshore than onshore, which may provide multiplebenefits, which may include, but are not limited to, greater alleviationof or positive impact on water scarcity, and lower cost of desalinatedwater produced (cost per m³ of desalinated water).

For example, by locating a desalination plant offshore, especially inlocations with deep water, desalination brine effluent may dilute moreeffectively and may be less harmful to marine life. For example,desalination brine effluent may disperse more effectively in open oceandue to greater water volume per unit of water body surface area, orpotentially greater ocean circulation, or potentially greater oceankinetic energy, or any combination thereof. For example, desalinationbrine effluent may be less harmful to marine life in open ocean becauseit may disperse more effectively, it may not be in contact with or inclose proximity to high-density marine habitats, such coral reefs, orkelp forests.

For example, locating a desalination plant offshore may reducedesalination pre-treatment costs due to the potentially lowerconcentration of suspended particles or sediments in the intake seawaterwater and due to the potentially more consistent composition andtemperature of the intake seawater.

For example, locating a desalination plant offshore may enable thedesalination plant to be powered irrespective of electricity griddisruptions or electricity shortages. For example, the desalinationplant may have an integrated energy storage system, or backup powergeneration, or both. For example, the desalination plant may be at leastpartially powered by offshore energy sources, which may include, forexample, offshore wind, or offshore solar, or wave power, or tidalpower, or ocean thermal energy conversion (OTEC) power, or natural gasor oil produced offshore, or any combination thereof.

For example, an offshore desalination plant may be unharmed by or maynot substantially be negatively impacted by earthquakes, forest fires,and tsunamis. In California, for example, forest fires are a commonoccurrence and earthquakes and tsunamis are a significant risk.

Some embodiments may comprise locating a desalination plant offshore andpowering the desalination plant using a connected power source. Forexample, the desalination plant may be connected to an onshore powersource, or electricity grid, or both using a subsea power cable. Forexample, the desalination plant may be connected to an offshore powersource, such as, for example, offshore wind, or offshore floating wind,or wave power, or tidal power, or floating solar, or offshore solar, oroffshore power generator, or ocean thermal energy conversion, or OTEC,or any combination thereof. For example, the desalination plant may beconnected to both an offshore and onshore power source. For example, thedesalination plant may be connected to one or more or a combination ofonshore and/or offshore power sources, or power consumers, or both.

Some embodiments may comprise storing energy or power by displacing ahigh density fluid with a low density fluid, and releasing ordischarging said stored energy by allowing said high density fluid todisplace said low density fluid, wherein said releasing or dischargingsaid stored energy or power comprises employing said released ordischarged stored energy to power the desalination of water, such assalt water or seawater.

In some embodiments, low density fluid may be transferred between alower elevation reservoir and a higher elevation reservoir, wherein thehigher elevation reservoir possesses an elevation higher than theelevation of the lower elevation reservoir. In some embodiments, highdensity fluid may be transferred between a higher elevation reservoirand a lower elevation reservoir, wherein the higher elevation reservoirpossesses an elevation higher than the elevation of the lower elevationreservoir. In some embodiments, a lower elevation reservoir may belocated beneath the surface of a liquid body, such as beneath thesurface of a body of water, or a solid body, such as beneath the surfaceof earth or other planet, or any combination thereof. In someembodiments, a higher elevation reservoir may be located above or on thesurface of a liquid body, such as the surface of a body of water, or asolid body, such as the surface of earth or other planet, or anycombination thereof. In some embodiments, a higher elevation reservoirmay be located beneath the surface of a liquid body, such as beneath thesurface of a body of water, or a solid body, such as beneath the surfaceof earth or other planet, or any combination thereof, although may belocated at substantially a greater elevation than the lower elevationreservoir. In some embodiments, a higher elevation reservoir may belocated in or on a floating vessel or platform. In some embodiments, ahigher elevation reservoir may be located on a land. In someembodiments, a lower elevation reservoir may be located underwater, orbeneath the surface of a water body, or on the seafloor or bottom of awater body, or tethered or suspended above the seafloor, or underground,or any combination thereof. In some embodiments, a higher elevationreservoir may be located underwater, or beneath the surface of a waterbody, or on the seafloor or bottom of a water body, or tethered orsuspended above the seafloor, or underground, or any combinationthereof. In some embodiments, the higher elevation reservoir may beconfigured to store low density liquid. In some embodiments, the lowerelevation reservoir may be configured to store high density liquid. Insome embodiments, the higher elevation reservoir may be configured tostore high density liquid. In some embodiments, the lower elevationreservoir may be configured to store lower density liquid. In someembodiments, the higher elevation reservoir may be configured to storehigh density liquid, or low density liquid, or any combination thereof.In some embodiments, the lower elevation reservoir may be configured tostore high density liquid, or low density liquid, or any combinationthereof.

In some embodiments, the lower elevation reservoir and the higherelevation reservoir may be configured to store low density fluid. Insome embodiments, the lower elevation tank may comprise a hydrostaticcompensation tank, or bladder tank, or membrane tank. In someembodiments, power or energy may be stored by pumping a low densityfluid into the subsea tank or lower elevation tank, expand thehydrostatic compensation tank, or bladder tank, or membrane tank anddisplacing ocean water or seawater. In some embodiments, power or energymay be generated by allowing the ocean water or seawater to displace thelow density fluid in the subsea tank or lower elevation tank, collapsingthe hydrostatic compensation tank, or bladder tank, or membrane tank andproducing a high pressure flow of low density fluid and/or pressureexchanging said high pressure flow of low density fluid withdesalination feed water in a desalination process.

In some embodiments, the lower elevation reservoir may be configured tostore low density fluid and high density fluid. In some embodiments, thelower elevation tank may comprise a rigid tank or at least partiallyrigid tank. In some embodiments, power or energy may be stored bypumping a low density fluid into the subsea tank or lower elevationtank, displacing a high density fluid. In some embodiments, power orenergy may be generated by allowing the high density fluid to displacethe low density fluid in the subsea tank or lower elevation tank andproducing a high pressure flow of low density fluid. In someembodiments, a pressure exchanger may be employed near the lowerelevation reservoir to pressure exchange between the high density fluidand the low density fluid, which may facilitate the displacement of highdensity fluid using low density fluid or the displacement of low densityfluid using high density fluid and/or may reduce stresses or requiredpressure resistance on the lower elevation reservoir or lower elevationreservoir tanks.

In some embodiments, high pressure low density fluid may be pressureexchanged with desalination feed water in a desalination process.

Some embodiments, may comprise employing the pressure of the low densityfluid, such as displaced low density fluid, to pressurize or otherwisepower the desalination of water, or saline water, or seawater.

For example, some embodiments may comprise pressure exchanging the highpressure low density liquid or a high pressure flow of low densityliquid with desalination feed water before or during the desalination ofat least a portion of said desalination feed water. Pressure exchangingmay comprise an energy efficient process to employ the stored energy topower at least a portion of desalination.

For example, some embodiments may employ a liquid with the same orsimilar composition to desalination feed water as a low density fluidand may involve employing the high pressure low density liquid as adesalination feed water. Some embodiments may involve employing apressure recovery device or pressure exchanger to extract power and/orreduce the pressure of the high pressure low density liquid to pressureappropriate for desalination feed water. Extracted pressure from saidpressure recovery device or pressure exchanger may be employed topressurize more desalination feed water, or to generate power, or togenerate electricity, or for another purpose, or for anotherapplication, or any combination thereof. Some embodiments may involveemploying a pressure recovery device or pressure exchanger to extractpower and/or reduce the pressure of the high pressure low density liquidand/or employing the low density liquid as a desalination feed water.Some embodiments may have the capability of pressure exchanging, oremploying high pressure low density liquid as desalination feed water,or employing low density liquid as desalination feedwater, or generatingpower from high pressure low density liquid, or any combination thereof.Some embodiments may have the capability of pressure exchanging, oremploying high pressure low density liquid as desalination feed water,or employing low density liquid as desalination feedwater, or generatingpower from high pressure low density liquid, or any combination thereofand/or may have the capability of increasing or decreasing orcontrolling the relative rates of or amount of pressure exchanging, oremploying high pressure low density liquid as desalination feed water,or employing low density liquid as desalination feedwater, or generatingpower from high pressure low density liquid, or any combination thereof.Employing a liquid comprising desalination feed water as a low densityfluid and employing the high pressure displaced low density fluid as adesalination feed may comprise an energy efficient process to employ thestored energy to power at least a portion of desalination.

For example, some embodiments may comprise generating power from thehigh pressure low density fluid or a high pressure flow of low densityfluid. Said generating of power may comprise generating electricity fromdisplacement of low density fluid, which may comprise generating powerfrom the high pressure low density fluid or a high pressure flow of lowdensity fluid. Some embodiments may involve employing said generatedpower to power pumps or other equipment in a desalination process. Forexample, some embodiments may involve employing said generated power topower pumps to pressurize desalination feed water. It may be desirableto generate electric power from the stored energy discharged during thedisplacement of low density fluid because it may provide flexibility inthe use of the power. For example, electricity may be used for otherapplications, or transmitted to an electricity grid, or employed topower pumps employed in desalination. For example, in some embodimentsor in some instances, generating electric power from the stored energydischarged during the displacement of low density fluid may provide moreflexibility in flow rates and pressures relative to a mechanicalpressure exchanger. For example, in some embodiments or in someinstances, generating electric power from the stored energy dischargedduring the displacement of low density fluid may allow for thedesalination feed water pressurization system to be a further distancefrom the power generation of power from the high pressure displacedliquid relative to some mechanical pressure exchangers.

For example, some embodiments may discharge or release or generate powerfrom at least a portion of said stored by pressure exchanging and/orpower generation. For example, some embodiments may be capable of bothpressure exchanging and/or power generation. For example, someembodiments controlling the level of pressure exchanging or powergeneration. For example, if demand for or value of electricity isgreater than desalinated water, the system may increase rate or amountor level of power generation or electric power generation relative tothe rate or amount or level of pressure exchanging. For example, ifdemand for or value of desalinated water is greater than electricity,the system may increase rate or amount or level of pressure exchangingrelative to the rate or amount or level of power generation or electricpower generation.

For example, some embodiments may be capable of powering desalinationusing grid electricity or other source of power in addition to orinstead of energy stored. For example, in some instances, it may bedesirable for at least a portion of the desalination process to bepowered by the discharging of energy stored and at least a portion ofthe desalination process to be powered by power from another source,such as electricity from an electricity grid, or solar, or wind, orgenerator, or offshore power source, or any combination thereof. Forexample, in some embodiments, it may be desirable for the system to haveat least a portion of control over the percentage or proportion of thedesalination process powered by stored energy and the percentage orproportion of the desalination process powered by other sources of poweror energy, such as electricity from an electricity grid, or solar, orwind, or generator, or offshore power source, or any combinationthereof. In some embodiments, said stored energy may comprise storedpower from said one or more sources of power or energy, which mayinclude, but are not limited to, electricity from an electricity grid,or solar, or wind, or generator, or offshore power source, or anycombination thereof. For example, in some instances, electricity fromone or more sources may be in excess, or may be at a low or favorablecost, and the system may procure or obtain electricity and allocate atleast a portion of said procured or obtained electricity for storage bymeans of fluid displacement energy storage and allocate at least aportion of said procured or obtained electricity to power a desalinationprocess. For example, in some instances, electricity from one or moresources may be in excess, or may be at a low or favorable cost, and thesystem may procure or obtain electricity and allocate at least a portionof said procured or obtained electricity for storage and allocate atleast a portion of said procured or obtained electricity to power adesalination process.

For example, in some embodiments, it may be desirable for the energystored in the system to comprise at least a portion of electricity orenergy or power sourced from or generated offshore. For example, in someembodiments, sourcing power from offshore may reduce the costs of thesystem or required scale of the subsea power cables because it mayeliminate the need for, or reduce the required scale of, or both asubsea power cable from shore or land. For example, in some embodiments,sourcing power from offshore may reduce the cost of the system orconstruction timeline or permitting requirements because sourcing poweroffshore may eliminate the need for a subsea cable connected to shore orland and the associated permitting, or trenching, or burying, or siting,or any combination thereof.

For example, some embodiments may comprise pressure exchanging the highpressure high density liquid or a high pressure flow of high densityliquid with desalination feed water before or during the desalination ofat least a portion of said desalination feed water. Pressure exchangingmay comprise an energy efficient process to employ the stored energy topower at least a portion of desalination.

There may be multiple potential benefits to pressure exchanging oremploying the power of high pressure fluid from the discharging of afluid displacement energy storage system to power desalination. Benefitsmay include, but are not limited to, one or more or any combination ofthe following:

For example, a direct or indirect pressure exchange may be significantlymore energy efficient than generating electricity from hydraulicpressure or the flow of fluid and then using said generated electricityto power an electric pump to pressurize the seawater feed. For example,hydraulic pressure exchangers may be up to 98% or 99% energy efficient,meaning, in some embodiments, energy stored in a high pressure lowdensity liquid or power in the high pressure low density liquid flow maybe transferred or converted or transformed into a high pressure seawaterfeed solution at an energy efficiency of about 98%. For example, theround trip energy efficiency of storing energy and then employing saidstored energy to power the pressurization of desalination feed water maybe, for example, 88%. For example, the pump employed to storeelectricity may be 90% efficient and the efficiency of converting thestored energy into pressurized desalination water feed may be 98%,meaning the total round trip efficiency may be 0.9*0.98 or 88%.

For comparison, generating electricity from hydraulic pressure, such ashydraulic pressure from a high pressure low density liquid, maygenerally be about 90% energy efficient, and using said generatedelectricity to power a pump to pressurize the seawater feed may be about90% energy efficient, meaning the energy efficiency of transformingstored energy in the form of gravitational potential energy or hydraulicpressure into a pressurized seawater feed solution via electricitygeneration and an electricity powered pump may be about 81% efficient,or 0.9*0.9.

For example, a direct or indirect pressure exchange may be significantlylower capital cost or CAPEX than generating electricity from hydraulicpressure or the flow of fluid and then using said generated electricityto power an electric pump to pressurize the seawater feed. For example,a hydraulic pressure exchanger may comprise a single unit or devicewhich directly or indirectly transfers the hydraulic pressure of thedisplaced fluid, such as the high pressure low density fluid, todesalination feed water. A hydraulic pressure exchanger may comprise amechanical pressure exchanger or a mechanical device or unit. Forcomparison, generating electricity from hydraulic pressure or flow offluid using a generator and then using the generated electricity topower a pump to pressurize the desalination feed water may require atleast two units, which may comprise a pump unit and a generator unit,which may be more expensive and more complex than a single pressureexchanger unit. Additionally, in some instances, a hydraulic orpneumatic or mechanical pressure exchanger may be lower cost than anequivalent capacity electric pump or electric generator because somepressure exchangers may not require substantial electrical components,including substantial electricity generation and/or electricitytransmission components, which may add complexity and/or cost.

In some embodiments, a pressure exchanger may transfer kinetic energy ormechanical work between two fluid streams, wherein the fluid streams areeach at different flow rates and pressures. For example, a pressureexchanger may transfer mechanical work or power from a high pressure lowdensity liquid with 150 Bar pressure and a first flow rate, to adesalination feed water stream, wherein the desalination feed waterstream has a second flow rate which is greater than said first flow rateand is pressurized from a starting pressure of 1 Bar to a resultingpressure of 68 Bar by the pressure exchanger. For example, a pressureexchanger may transfer mechanical work or power from a high pressure lowdensity liquid with 150 Bar pressure and a first flow rate, to adesalination feed water stream, wherein the desalination feed waterstream has a second flow rate which is greater than said first flow rateand is pressurized from a starting pressure of 30 Bar to a resultingpressure of 68 Bar by the pressure exchanger.

For example, a direct or indirect pressure exchange may enable the useof different fluids for energy storage than the desalination feed water.For example, a direct or indirect pressure exchange may enable the useof fluids which may comprise a different composition than desalinationfeed water as the high pressure low density liquid. For example, adirect or indirect pressure exchange may enable the use of fluids whichmay be soluble in the desalination feed water, or incompatible with thedesalination feed water, a different temperature than the desalinationfeed water, or reactive with the desalination feedwater, or comprise achemical other than desalination feed water, or any combination thereof.

There may be multiple potential benefits to employing at least a portionof the desalination feed water as a low density fluid in an energystorage system.

For example, employing the desalination feed water as a low density inthe energy storage system may enable a greater round trip energyefficiency of the energy storage system if at least a portion of theenergy stored in the energy storage system is employed to powerdesalination. For example, in some embodiments, discharging the energystorage system may involve a high density fluid, which may comprise afluid with a greater density than the desalination feed water,displacing a low density fluid, which may comprise desalination feedwater, and resulting in the low density fluid becoming a high pressurelow density fluid stream. For example, in some embodiments, said highpressure low density fluid stream comprising desalination feed water maybe transferred or directed into a reverse osmosis desalination processor other desalination process. For example, in some embodiments, saidhigh pressure low density fluid stream comprising desalination feedwater may be transferred or directed into a reverse osmosis desalinationprocess or other desalination process, wherein the pressure of the highpressure low density fluid stream comprising desalination feed water maybe sufficiently high to overcome the osmotic pressure of the dissolvedsalts or solutes and produce at least a portion of desalinated waterpermeate and/or at least a portion of retentate brine or desalinationbrine effluent. In some embodiments, transferring the high pressure lowdensity fluid stream comprising desalination feed water into a reverseosmosis or other pressure driven desalination system may enable a higherenergy efficiency because it may reduce the amount or level ofmechanical or electrical conversions or exchanges to achieve thedischarge of stored energy to power at least a portion of desalination.For example, in some embodiments, the round trip energy efficiency maybe about 90%, because the pump employed to initial store energy bydisplacing a high density fluid using a low density fluid may have anenergy efficiency of 90%, and releasing said stored energy may beconducted by allowing the high density fluid to displace the low densityfluid with minimal additional mechanical exchange or facilitated by ahigh efficiency pressure exchanger. In some embodiments, if the pressureof the high pressure low density fluid may be greater than a desiredpressure, such as the required pressure for desalination, and/or apressure exchanger may extract or exchange a portion of pressure orpower to reduce the pressure of the high pressure low density fluid to adesired pressure and/or employ the extracted pressure to pressurizeanother fluid, such as additional desalination feed water. In someembodiments, if the pressure of the high pressure low density fluid maybe greater than a desired pressure, such as the required pressure fordesalination, and/or a hydraulic power recovery turbine or generator mayextract power and/or generate electricity to reduce the pressure of thehigh pressure low density fluid to a desired pressure and/or employ ortransmit or sell or use said generated electricity. In some embodiments,the pressure of the high pressure low density fluid may be lower thanthe pressure required to overcome the osmotic pressure for desalinationand the pressure of the high pressure low density fluid may be increasedusing, for example, including, but not limited to, one or more or anycombination of the following: a booster pump, or a pressure exchanger,or pressure exchanger with retentate solution, or other pressureexchanger, or other pressure increasing mechanism.

For example, employing the desalination feed water as a low density inthe energy storage system may reduce capital cost because it may reducethe need for or amount of mechanical pressure exchange or powergeneration equipment, or reduce system complexity, or any combinationthereof.

In some embodiments there may be more than one pressure exchange. Forexample, in some embodiments, including but not limited to, a pressureexchanger may be employed to extract or exchange or transfer power orpressure from a high pressure low density fluid, or a pressure exchangermay be employed to extract or exchange or transfer power or pressurefrom desalination brine effluent or retentate brine, or any combinationthereof.

In some embodiments, the low density fluid in an energy storage systemmay comprise desalination feed water. In some embodiments, the highdensity fluid in an energy storage system may comprise desalination feedwater. In some embodiments, the low density fluid in an energy storagesystem may comprise desalination brine effluent or retentate. In someembodiments, the high density fluid in an energy storage system maycomprise desalination brine effluent or retentate. In some embodiments,the high density fluid in an energy storage system may comprise furtherdesalination brine effluent or retentate, which may have been furtherconcentrated using, for example, including, but not limited to, one ormore or any combination of the following: evaporation, or distillation,or membrane distillation, or forward osmosis, or high pressure reverseosmosis, or high pressure nanofiltration, or DTRO, or osmoticallyassisted reverse osmosis, or cryodesalination. In some embodiments, thelow density fluid in an energy storage system may comprise desalinatedwater or freshwater. In some embodiments, the high density fluid in anenergy storage system may comprise desalinated water or freshwater.

For example, some embodiments may comprise storing the desalinatedwater.

For example, in some embodiments, desalinated water may be stored insubsea storage tanks. In some embodiments, said subsea storage tanks maycomprise bladder tanks or membrane tanks or other tanks in pressureequilibrium or pressure compensation with the surrounding or adjacentocean and/or which involve desalinated water indirectly or displacingseawater. In some embodiments, because desalinated freshwater may beless dense than seawater, pumping desalinated water into the subsea tankmay require more energy than pumping desalinated water out of the subseatank because of the buoyancy of the desalinated freshwater in theseawater, and/or storing desalinated water subsea may comprise storingat least a portion of fluid displacement gravitational potential energy.

For example, in some embodiments, desalinated water may be stored infloating storage tanks, or floating storage vessels. In someembodiments, said floating storage vessel may comprise ships which storeliquids and may be designed to transport liquids, such as desalinatedwater. In some embodiments, said floating storage vessel may comprise avessel wherein at least a portion is located beneath the surface of awater body, although the vessel itself may be above or suspended abovethe seafloor. In some embodiments, said floating storage vessel maycomprise a floating vessel in pressure equilibrium with the air. In someembodiments, said floating storage vessel may comprise a floating vesselin pressure equilibrium with the air, for example, by means of,including, but not limited to, a bladder tank, or floating roof, ordirect liquid-air interface, or any combination thereof.

For example, in some embodiments, desalinated water may comprise a lowdensity fluid in the energy storage system, and at least a portion ofdesalinated water may be stored while being employed as a low densityliquid in the energy storage system. For example, in some embodiments,desalinated water may have a dual purpose of functioning as a lowdensity fluid in a fluid displacement energy storage system and/or aswater stored for a later transfer, or transport, or distribution, orconsumption, or other use.

For example, in some embodiments, desalinated water may comprise a highdensity fluid in the energy storage system, and at least a portion ofdesalinated water may be stored while being employed as a high densityliquid in the energy storage system. For example, in some embodiments,desalinated water may have a dual purpose of functioning as a highdensity fluid in an fluid displacement energy storage system and/or aswater stored for a later transfer, or transport, or distribution, orconsumption, or other use.

For example, in some embodiments, desalinated water may comprise a lowdensity fluid in the energy storage system, wherein the desalinatedwater may be stored in a higher elevation reservoir, or a lowerelevation reservoir, or both depending on the state of charge or levelof charge or level of energy stored in the energy storage system. Insome embodiments, the lower elevation reservoir may comprise a rigidtank, which may sometimes store both high density fluid and low densityfluid. In some embodiments, the lower elevation reservoir may comprise atank storing low density fluid separate or non-contiguously separatefrom a tank storing high density fluid and/or said tank or tanks maycomprise a rigid tank, or bladder tank, or pressure compensated tank, ortank at pressure equilibrium with the surrounding or adjacent seawater,or any combination thereof, and/or wherein a pressure exchange may beemployed to enable or facilitate the displacement of low density fluidwith high density fluid, or high density fluid with low density fluid,or any combination thereof.

For example, in some embodiments, desalinated water may comprise a highdensity fluid in the energy storage system, wherein the desalinatedwater may be stored in a higher elevation reservoir, or a lowerelevation reservoir, or both depending on the state of charge or levelof charge or level of energy stored in the energy storage system. Insome embodiments, the lower elevation reservoir may comprise a rigidtank, which may sometimes store both high density fluid and low densityfluid. In some embodiments, the lower elevation reservoir may comprise atank storing low density fluid separate or non-contiguously separatefrom a tank storing high density fluid and/or said tank or tanks maycomprise a rigid tank, or bladder tank, or pressure compensated tank, ortank at pressure equilibrium with the surrounding or adjacent seawater,or any combination thereof, and/or wherein a pressure exchange may beemployed to enable or facilitate the displacement of low density fluidwith high density fluid, or high density fluid with low density fluid,or any combination thereof.

Note: Adding a high density fluid to a reservoir, wherein the additionof the high density fluid into the reservoir, or the process oftransferring the high density fluid to the reservoir, or the process oftransferring the high density fluid between reservoirs, or anycombination thereof results in removal or exiting of low density fluidfrom said reservoir may comprising ‘displacing’ low density fluid or‘displacement’ of low density fluid.

Note: Adding a low density fluid to a reservoir, wherein the addition ofthe low density fluid into the reservoir, or the process of transferringthe low density fluid to the reservoir, or the process of transferringthe low density fluid between reservoirs, or any combination thereofresults in removal or exiting of high density fluid from said reservoirmay comprising ‘displacing’ high density fluid or ‘displacement’ of highdensity fluid.

In some embodiments, the pump employed in storing energy may also beemployed as a generator to generate electricity.

Desalination processes or regeneration processes or separation processesmay include, but are not limited to, one or more or a combination of thefollowing: reverse osmosis, or nanofiltration, or semi-permeablemembrane based process, or mechanical vapor compression distillation, orvacuum distillation, or distillation, or membrane distillation, orforward osmosis, or solar desalination, or condensation, or osmoticallyassisted reverse osmosis, or DTRO, or electrodialysis, orcryodesalination, or high pressure reverse osmosis, or high pressurenanofiltration, or precipitation, or solventing-out, or extraction, orextractive distillation.

Some embodiments may involve transferring or transporting desalinatedwater from the offshore desalination plant to an onshore application, orto a transmission site, or a municipal water plant, or a municipal waterdistribution system, or city water distribution system, or an industrialwater user or water consumer, or any combination thereof. In someembodiments, desalinated water may be transferred using a pipeline. Insome embodiments, desalinated water may be transported using a ship, orsubmarine, or both. In some embodiments, desalinated water may betransported using a subsea pipeline, or suspended pipeline, or floatingpipeline. In some embodiments, desalinated water may be transportedusing a conveyor belt, or a train. In some embodiments, desalinatedwater may be transported using an aircraft.

Some embodiments may involve using the desalinated water.

For example, some embodiments may involve employing the desalinatedwater to produce hydrogen. For example, some embodiments may involveemploying the desalinated water to produce hydrogen derivatives, such asammonia, or chemicals. For example, some embodiments may involveemploying the desalinated water to produce chemicals. For example, someembodiments may involve employing the desalinated water to produce CO₂derived chemicals. For example, some embodiments may involve employingthe desalinated water to produce oxygen or liquid oxygen. For example,some embodiments may involve employing the desalinated water to producerocket fuel, or fuel for a space ship, or fuel for a space port. Forexample, some embodiments may involve employing the desalinated water toproduce hydrogen peroxide. For example, some embodiments may involveemploying the desalinated water to produce synthetic fuels, or renewablefuels, or renewable energy derived chemicals, or low carbon chemicals,or low carbon emission chemicals, or lower carbon footprint chemicals orfuels, or any combination thereof. For example, some embodiments mayinvolve producing said chemicals or fuels offshore. For example, someembodiments may involve producing said chemicals or fuels onshore.

For example, some embodiments may involve producing chemicals or fuelsfrom desalinated water offshore, then transferring or transporting saidchemicals or fuels. For example, said chemicals or fuels may betransported using one or more or any combination of vessels, such asships. For example, said chemicals or fuels may be transported using oneor more or a combination of pipelines. In some embodiments, saidchemicals or fuels may be transferred or transported to applications oruses onshore. For example, in some embodiments, said chemicals or fuelsmay be employed to, for example, including, but not limited to, one ormore or any combination of the following: fuel vessels, or fuel cars, orfuel trains, or fuel airplanes, or fuel ships, or fuel trucks, or heator cool, or generate electricity, or produce chemicals, or use in one ormore applications, or manufacture, or use in manufacturing, or produceproducts. In some embodiments, said chemicals or fuels may betransferred or transported to applications or uses offshore. Forexample, in some embodiments, said fuels may be employed to fuel-up orpower ships, or marine vessels, or aircraft, or military aircraft, ormilitary vessels, or military equipment, or equipment, or marineequipment, or autonomous vehicles, or offshore ports, or powergeneration equipment, or pumping equipment, or land vehicles, or surfacevehicles, or subsea vehicles, or subsea equipment, or rockets, orspaceships, or space vehicles, or spaceports, or floating space ports,or CO₂ capture, or any combination thereof.

For example, some embodiments may involve employing synthesizedchemicals as the low density fluid, or the high density fluid, or anycombination thereof in the energy storage system. Employing synthesizedchemicals as the low density fluid, or the high density fluid, or anycombination thereof in the energy storage system may enable a dualpurpose for the chemicals, which may involve simultaneous storage of thechemicals for sale or other use, and use of the chemicals for storing orgenerating power in the form of gravitational potential energy.

For example, some embodiments may involve using the desalinated waterfor offshore use or offshore consumption. For example, some embodimentsmay involve using the desalinated water for human consumption. Forexample, some embodiments may involve using the desalinated water foroffshore agricultural use. For example, some embodiments may involveusing the desalinated water for aquaculture. For example, someembodiments may involve using the desalinated water for the extraction,or production, or mining, or processing, or operation, or anycombination thereof of natural resources, or oil, or natural gas, orclathrates, or minerals, or materials, or any combination thereof,

Some embodiments may comprise an offshore data center.

Desalination feed water may comprise the liquid from which adesalination process extracts water or produces desalinated water or thewater source or the feedstock to produce desalinated water. For example,desalination feed water or feed water may comprise seawater or treatedseawater.

Example Notes:

Locating desalination offshore potential benefits may include, but arenot limited to:

No land use

Lower cost

Less permitting

More scalable

Less potential harm to marine life, greater effluent dilution, feedwatercontains less particulates, lower pretreatment costs,

Long duration energy storage to enable greater percentage of renewablepower generation or renewable power for desalination

Fluid displacement energy storage to store energy. In some embodiments,said energy may comprise electricity from renewable electricity sources,such as solar or wind.

Energy may be stored in the form of gravitational potential energy

Generating energy from the stored power may comprise allowing a highdensity fluid to displace a low density fluid, generating a highpressure low density liquid or a high pressure flow of low densityfluid. In some embodiments, the high pressure low density fluid may bepressure exchanged with seawater feed, which may mechanically pressurizethe seawater feed before or while feeding said seawater feed into adesalination process, such as a reverse osmosis process.

A direct or indirect pressure exchange may be significantly more energyefficient than generating electricity from said hydraulic pressure andthen using said generated electricity to power an electric pump topressurize the seawater feed. For example, hydraulic pressure exchangersmay be about 98% energy efficient, meaning energy stored in a highpressure low density liquid may be transferred or converted ortransformed into a high pressure seawater feed solution at an energyefficiency of about 98%. For comparison, generating electricity fromhydraulic pressure, such as hydraulic pressure from a high pressure lowdensity liquid, may generally be about 90% energy efficient, and usingsaid generated electricity to power a pump to pressurize the seawaterfeed may be about 90% a energy efficient, meaning the energy efficiencyof transforming stored energy in the form of gravitational potentialenergy or hydraulic pressure into a pressurized seawater feed solutionvia electricity generation and an electricity powered pump may be about81% efficient, or 0.9*0.9.

In most seawater reverse osmosis desalination processes, the most energyintensive part of desalination may be the pressurization of the seawaterfeed solution to overcome the osmotic pressure of the seawater andenable the extraction of freshwater from the seawater.

In some embodiments, said low density fluid may comprise seawater ortreated seawater. In some embodiments, said high pressure low densityfluid may comprise seawater and may comprise the feed solution to adesalination process, such as a reverse osmosis desalination process.

If electricity, such as renewable electricity, may be generatedoffshore, may eliminate need for a subsea transmission cable back toshore.

For example, electricity may comprise electricity generated offshore

In some embodiments, a subsea power cable may transfer electricity fromshore to the offshore energy storage and desalination process, where theelectricity may be used to power desalination, or may be stored usingliquid displacement energy storage, or both.

Resilience—power in event of electricity grid disruptions or electricityshortages

Potentially less impacted by earthquakes and forest fires

Desalinated water may be transferred to shore or other application byship, or pipeline

Desalinated water may be employed in the production of hydrogen. Forexample, desalinated water may be employed in the production of hydrogenfrom the electrolysis of water, or thermolysis of water, or anycombination thereof. For example, desalinated water may be employed inthe production of hydrogen using the water gas shift process. Forexample, desalinated water may be employed in the production ofhydrogen, or syngas, or other valuable energy carrier or materialfeedstock or material by creating steam for gasification of carbonaceousmaterials. Desalinated water may be employed in another industrialapplication involving the use of water.

In some embodiments, electricity may be transferred by a ship

Internal storage for desalinated water

High Density Liquid May Comprise Flow Battery Electrolyte (such asvanadium oxide, or iron oxide flow battery electrolyte)

In some embodiments, the high density fluid, or low density fluid, orboth may comprise a flow battery electrolyte. Energy may be stored inthe gravitational potential energy storage of low density fluiddisplacing high density fluid, or the flow battery electrolyte'schemical energy storage or state of charge, or any combination thereof.

In the present example, high density fluid may comprise flow batteryelectrolyte.

In some embodiments, when charging, low density fluid in a highelevation region reservoir may be pumped to displace the high densityfluid in a low elevation reservoir, resulting in the low density fluidentering or filling the low elevation reservoir and the high densityfluid entering or filling the high elevation reservoir. Fluids may betransferred between the low elevation reservoir and high elevationreservoir using one or more pipes or pipelines. Said high density fluidmay comprise ‘discharged’ or low charge state flow battery electrolyte.

In the higher elevation region, the high density fluid, which maycomprise discharged flow battery electrolyte, may be stored in a highelevation high density fluid storage tank configured to store dischargedflow battery electrolyte. Additional energy or electricity may be storedby charging the discharged flow battery electrolyte, which may involvetransferring the discharged flow battery electrolyte through a chargingmechanism, such as an AEM and/or CEM, wherein the discharged flowbattery electrolyte is transformed into a charged flow batteryelectrolyte by charging said flow battery electrolyte by anelectrochemical reaction or by means of electricity, or by means oflight, or by means of photons, or by means of introduction of an energycarrier, or any combination thereof, and then transferring and/orstoring the charged flow battery electrolyte a high elevation regionhigh density fluid storage tank, which may be configured to storecharged flow battery electrolyte.

In some embodiments, when discharging, electricity may be generated bydischarging or generating power from at least a portion of the chargedflow battery electrolyte by transferring said charged flow batteryelectrolyte from the charged flow battery electrolyte storage tank intoa discharging or power generating mechanism, such as an AEM and/or CEM,and generating electricity or power, and forming discharged flow batteryelectrolyte, and transferring said formed discharged flow batteryelectrolyte into a high elevation region discharged flow batteryelectrolyte storage reservoir, which may comprise a high elevationregion high density fluid storage reservoir. Additional electricity maybe generated or the energy storage system may be further discharged byallowing discharged flow battery electrolyte in the high elevationregion discharged flow battery electrolyte storage reservoir to betransferred from the higher elevation region to the lower elevationregion, displacing the low density fluid in the lower elevation regionor lower elevation reservoir, and generating power from the highpressure displaced low density fluid. Fluids may be transferred betweenthe low elevation reservoir and high elevation reservoir using one ormore pipes or pipelines.

In some embodiments, at least a portion of the discharged flow batteryelectrolyte may be charged while or after being transferred to thehigher elevation region, which may reduce the required scale of oreliminate the need for the higher elevation discharged flow batteryelectrolyte storage reservoir.

In some embodiments, the charged flow battery electrolyte may beemployed as a high density fluid in the energy storage system.

Flow battery electrolyte, or other high density liquid, or other lowdensity liquid, or low density liquid, or high density liquid, or anycombination thereof may comprise a fluid. Said fluid may include, but isnot limited to, one or more or any combination of the following: aliquid, a gas, a solid, a supercritical fluid, an emulsion, orsolid-liquid mixture, a superfluid, a suspension, a solid-liquid, aphase change material, a gas-liquid mixture, or a pumpable substance, ora pumpable substance under certain conditions, or any combinationthereof.

Example electrolytes may include, but are not limited to, iron,vanadium, manganese

Example Notes:

Energy storage system wherein the low density fluid, during discharge,may be pressure exchanged, using a pressure exchanger, with seawaterfeed for desalination using reverse osmosis.

Example Advantages:

Hydraulic pressure exchanger may be more energy efficient than electricturbine or generator, increasing round trip energy efficiency

Hydrogen production may require ‘freshwater’—to produce hydrogen,generally water employed may be required to be freshwater, someembodiments of the present invention may function as the desalinationsystem to produce the freshwater required to produce hydrogen

Ocean water feed may be from deep, open ocean

Feed seawater may be better water quality (for example: lessparticulates and pre-treatment)

Feed seawater may not need to be transported by an open intake pipelineonshore, which may be invasive to the shoreline and environment

Feedwater pipeline may be shorter in length

Feedwater pipeline may not need to be buried

Feed seawater pipeline and water extraction significantly may be lessimpactful on the marine environment

Some embodiments may have no or practically no land use

Some embodiments may involve no or minimal shoreline use or shorelinedestruction

Some embodiments may enable practically infinitely scalable desalinationwith minimal impact to shoreline or coastal real estate

Potential for near 100% renewable desalination−desalination plant withbuilt-in energy storage for renewable energy storage

Potentially lower permitting and environmental mitigation costs(especially expensive in California)

“The Carlsbad plant project cost has been estimated at approximately$650 million (3,400 m3/day) (Global Water Intelligence 2016), with abouthalf of that cost related to permitting and environmental mitigation.”

Possible location—Offshore Moss Landing California, with subseatransmission cable from Moss Landing Power Plant/Energy Storage locationor from a floating offshore wind farm

In some embodiments, HDL or LDL may themselves comprise reverse osmosisfeed (e.g. HDL may be seawater or LDL may be seawater)—furtherincreasing round trip energy efficiency because, if the LDL is seawater,no pressure exchange may be required.

Some embodiments may involve internal fresh/desalinated water storage

Electricity or power may be generated from renewable energy sources,such as floating solar, or floating wind, or offshore wind, or offshoresolar, or wave power, or tidal power, or ocean thermal energyconversions, or salinity gradient power generation

Some embodiments may transfer water to shore rather than electricity

Greater round trip energy efficiency

Water is transferred to shore instead of electricity

Electricity may be generated offshore

Electricity or power may be generated from renewable energy sources,such as floating solar, or floating wind, or offshore wind, or offshoresolar, or wave power, or tidal power, or ocean thermal energyconversions

Electricity or power may be generated from nuclear power

Electricity or power may be generated from the combustion of one or morehydrocarbons

Further lowering cost by potentially eliminated need for a subsea powertransmission cable to or from shore

An electric or otherwise renewable powered ship may transport water fromthe desalination plant. Multiple ships from multiple ports may beemployed to ship the desalinated water to various parts of, for example,California or elsewhere

In some embodiments, desalination may occur solely using hydraulicpressure exchange as pressure source

In some embodiments, desalination may occur using hydraulic pressureexchanger when electricity is not available or too expensive (forexample: during energy storage discharge) and using electric power whenelectricity is available and/or low cost and/or affordable

Potential Integration with Offshore Renewables

Long duration energy storage to enable greater percentage of renewablepower generation

Fluid displacement energy storage to store energy. In some embodiments,said energy may comprise electricity from renewable electricity sources,such as solar or wind.

Energy may be stored in the form of gravitational potential energy

Generating energy from the stored power may comprise allowing a highdensity fluid to displace a low density fluid, generating a highpressure low density liquid or a high pressure flow of low densityfluid. In some embodiments, the high pressure low density fluid may bepressure exchanged with seawater feed, which may mechanically pressurizethe seawater feed before or while feeding said seawater feed into adesalination process, such as a reverse osmosis process.

A direct or indirect pressure exchange may be significantly more energyefficient than generating electricity from said hydraulic pressure andthen using said generated electricity to power an electric pump topressurize the seawater feed. For example, hydraulic pressure exchangersmay be about 98% energy efficient, meaning energy stored in a highpressure low density liquid may be transferred or converted ortransformed into a high pressure seawater feed solution at an energyefficiency of about 98%. For comparison, generating electricity fromhydraulic pressure, such as hydraulic pressure from a high pressure lowdensity liquid, may generally be about 90% energy efficient, and usingsaid generated electricity to power a pump to pressurize the seawaterfeed may be about 90% energy efficient, meaning the energy efficiency oftransforming stored energy in the form of gravitational potential energyor hydraulic pressure into a pressurized seawater feed solution viaelectricity generation and an electricity powered pump may be about 81%efficient, or 0.9*0.9.

In most seawater reverse osmosis desalination processes, the most energyintensive part of desalination may be the pressurization of the seawaterfeed solution to overcome the osmotic pressure of the seawater andenable the extraction of freshwater from the seawater.

In some embodiments, said low density fluid may comprise seawater ortreated seawater. In some embodiments, said high pressure low densityfluid may comprise seawater and may comprise the feed solution to adesalination process, such as a reverse osmosis desalination process.

If electricity, such as renewable electricity, may be generatedoffshore, may eliminate need for a subsea transmission cable back toshore. For example, said renewable electricity may comprise

In some embodiments, a subsea power cable may transfer electricity fromshore to the offshore energy storage and desalination process, where theelectricity may be used to power desalination, or may be stored usingliquid displacement energy storage, or both.

Resilience—power in event of electricity grid disruptions or electricityshortages

Desalinated water may be transferred to shore or other application byship, or pipeline

Desalinated water may be employed in the production of hydrogen. Forexample, desalinated water may be employed in the production of hydrogenfrom the electrolysis of water, or thermolysis of water, or anycombination thereof. For example, desalinated water may be employed inthe production of hydrogen using the water gas shift process. Forexample, desalinated water may be employed in the production ofhydrogen, or syngas, or other valuable energy carrier or materialfeedstock or material by creating steam for gasification of carbonaceousmaterials. Desalinated water may be employed in another industrialapplication involving the use of water.

In some embodiments, electricity may be transferred by a ship

Internal storage for desalinated water

DETAILED FIGURE DESCRIPTIONS

FIGS. 1-4

FIGS. 1-4 Description

FIGS. 1-4 may show a tank of a storage reservoir which may be configuredto store low density fluid and high density fluid. FIGS. 1-4 may showthe changes in relative fluid amounts and fluid-fluid interface levelduring charging and discharging of some embodiments of energy storagesystem. FIG. 2 and FIG. 4 may represent a higher elevation reservoirtank during charging or storing power in the energy storage system, ormay represent a lower elevation reservoir tank during discharging orgenerating power from the energy storage system. FIG. 1 and FIG. 3 mayrepresent a higher elevation reservoir tank during discharging orgenerating power from the energy storage system, or may represent alower elevation reservoir tank during charging or storing power in theenergy storage system.

FIGS. 1 and 2 may provide ‘liquid-liquid interface’ as an examplefluid-fluid interface. Fluid-fluid interfaces instead of, or in additionto, liquid-liquid interfaces may be employed, and may, for example,include, but are not limited to, one or more or any combination of thefollowing: liquid-liquid interfaces, or gas-liquid interfaces, or[solid-liquid]—liquid interfaces, or emulsion—liquid interfaces, orsuspension—liquid interfaces, or suspension—suspension interfaces, or[solid-liquid]—[solid-liquid] interfaces, or gas-suspension interfaces,or gas—emulsion interfaces, or interfaces comprising at least one fluidcomprising a supercritical fluid, or supercritical fluid—liquidinterfaces.

FIG. 1 and FIG. 2 may show a tank of a storage reservoir with a directfluid-fluid interface or direct contact between the low density fluidand high density fluid within a storage reservoir tank. In someembodiments, it may be desirable to employ tanks configured with adirect fluid-fluid interface when the system may be designed to have thehigh density fluid and low density fluid practically mutually insoluble,or have the high density fluid and low density fluid mutually nearlyfully saturated at solubility limits, or any combination thereof. Insome embodiments, tanks configured with direct fluid-fluid interface mayemploy high density fluid and low density fluid which are mutuallysoluble. In some embodiments, tanks configured with direct fluid-fluidinterface employing a high density fluid and low density fluid which aremutually soluble may possess a stratification layer or cline layer orchemocline at the interface between the low density fluid and highdensity fluid, which may comprise a varying concentration of highdensity fluid components and/or low density fluid components dependingon location or elevation within the stratification layer or cline layeror chemocline layer.

FIG. 3 and FIG. 4 may show a tank of a storage reservoir with a divideror barrier which at least partially occupies a region which mayotherwise be occupied by a direct fluid-fluid interface within a storagereservoir tank. In some embodiments, a divider or barrier at afluid-fluid interface or a hypothetical fluid-fluid interface may reducethe surface area of a direct fluid-fluid interface, or reduce thesurface area by which a high density fluid is in direct contact with alow density fluid, or any combination thereof. In some embodiments, adivider or barrier at a fluid-fluid interface or a hypotheticalfluid-fluid interface may reduce the rate or amount of mixing betweenthe low density fluid and/or high density fluid within a tank relativeto embodiments with a direct fluid-fluid interface, which may reduce therate of contamination or dilution of the high density fluid, or lowdensity fluid, or both. In some embodiments, it may be desirable toemploy at least a portion of a barrier or divider at a fluid-fluidinterface between a high density fluid and low density fluid wherein thehigh density fluid may be at least a portion soluble in the low densityfluid, or wherein the low density fluid may be at least a portionsolution in the high density fluid, or any combination thereof.

In some embodiments, a portion of one or more chemical constituents ofthe higher density fluid may dissolve in the lower density fluid. It maybe desirable to regenerate or otherwise remove said one or more chemicalconstituents of the higher density fluid from the lower density fluid.It may be desirable to employ systems for regenerating or otherwiseremoving said one or more chemical constituents of the higher densityfluid from the lower density fluid using one or more or a combination ofseparation methods or processes.

In some embodiments, a portion of one or more chemical constituents ofthe lower density fluid may dissolve in the higher density fluid. It maybe desirable to regenerate or otherwise remove said one or more chemicalconstituents of the lower density fluid from the higher density fluid.It may be desirable to employ systems for regenerating or otherwiseremoving said one or more chemical constituents of the lower densityfluid from the higher density fluid using one or more or a combinationof separation methods or processes.

Example FIGS. 1-4 Key

Example FIGS. 1-4 Key Label in Figure Description Low Density Lowdensity fluid or lower density fluid may comprise a fluid within anfluid Fluid displacement energy storage system which possesses a densityless than the density of the higher density fluid within the systemunder at least a portion of the operating conditions within the system.For example, some embodiments may employ a low density fluid and a highdensity fluid, wherein energy or power may be stored by displacing atleast a portion of high density fluid in a lower elevation region to ahigher elevation region using a low density fluid transferred from ahigher elevation region. IN ‘IN’ may represent the flow or movement of afluid into a tank. For example, ‘IN’ may represent that the amount of agiven fluid is increasing within a tank. For example, ‘IN’ may representthat the rate of a given fluid entering the tank or reservoir ispositive in a given location within a tank or reservoir, or the rate ofchange of an amount of a fluid within a tank net positive, or anycombination thereof. For example, in FIG. 1 and FIG. 3, ‘IN’ may show alow density fluid entering a tank or being added to a tank or flowinginto a tank. For example, in FIG. 2 and FIG. 4, ‘IN’ may show a highdensity fluid entering a tank or being added to a tank or flowing into atank. High Density High density fluid or higher density fluid maycomprise a fluid within an fluid Fluid displacement energy storagesystem which possesses a density greater than the density of the lowerdensity fluid within the system under at least a portion of theoperating conditions within the system. For example, some embodimentsmay employ a low density fluid and a high density fluid, wherein energyor power may be stored by displacing at least a portion of high densityfluid in a lower elevation region to a higher elevation region using alow density fluid transferred from a higher elevation region. OUT ‘OUT’may represent the flow or movement of a fluid out of or from a tank. Forexample, ‘OUT’ may represent that the amount of a given fluid isdecreasing within a tank. For example, ‘OUT’ may represent that the rateof a given fluid exiting the tank or reservoir is positive in a givenlocation within a tank or reservoir, or the rate of change of amount offluid within a tank may be net negative, or any combination thereof. Forexample, in FIG. 1 and FIG. 3, ‘OUT’ may show a high density fluidexiting a tank or being removed from a tank or flowing out of a tank.For example, in FIG. 2 and FIG. 4, ‘OUT’ may show a low density fluidexiting a tank or being removed from a tank or flowing out of a tank.Liquid-Liquid A liquid-liquid interface may be provided as an examplefluid-fluid interface. Interlace In some embodiments, a fluid-fluidinterface may comprise where a high density fluid and a low densityfluid meet or intersect. In some embodiments, a direct fluid-fluidinterface may comprise where a high density fluid and a low densityfluid are in direct physical contact. In some embodiments, a fluid-fluid interface may comprise a stratification or cline layer where highdensity fluid transitions into low density fluid or vise versa. In someembodiments, the position or elevation of a liquid-liquid interface maychange if for example, including, but not limited to, one or more or anycombination of the following changes: the relative volume of highdensity fluid to low density fluid, or the total volume of high densityfluid, or the total volume of low density fluid, or any combinationthereof or the composition of low density fluid, or the composition ofhigh density fluid. Some embodiments may employ or involve ahypothetical fluid-fluid interface or hypothetical liquid- liquidinterface. In some embodiments, a hypothetical fluid-fluid interface maycomprise where a fluid-fluid interface may exist or be present, if, forexample, a barrier or divider was not present. Floating A floatingbarrier may comprise a barrier or divider which may occupy a Barrierregion between a low density fluid and high density fluid within a tankor other storage vessel and/or may be located at or near a fluid-fluidinterface or a hypothetical fluid-fluid interface. In some embodiments,the barrier or divider may be floating, for example, wherein the densityof the floating barrier or divider may be greater than the density ofthe low density fluid and/or less than the density of the high densityfluid. In some embodiments, the barrier or divider may be of a greaterdensity than the higher density fluid, or may be of a lesser densitythan the lower density fluid, or any combination thereof. In someembodiments, the barrier or divider may adjust its position with passivemechanisms, or active mechanisms, or any combination thereof.

FIGS. 1-4 Example Step-by-Step Description

At least a portion of low density fluid is transferred into the topregion of the tank, displacing at least a portion of high density fluidbelow the low density fluid, wherein at least a portion of high densityfluid exits from the bottom region of the tank. As low density fluidenters the tank and high density fluid is displaced, the position of thefluid-fluid interface or hypothetical fluid-fluid interface within thetank may change. For example, the position or elevation of thefluid-fluid interface or hypothetical fluid-fluid interface maydecrease. If a barrier or divider is present, the position of thebarrier or divider may change to match or nearly match the change inposition or elevation of the fluid-fluid interface or hypotheticalfluid-fluid interface.

At least a portion of high density fluid is transferred into the bottomregion of the tank, displacing at least a portion of low density fluidabove the high density fluid, wherein at least a portion of low densityfluid exits from the top region of the tank. As high density fluidenters the tank and low density fluid is displaced, the position of thefluid-fluid interface or hypothetical fluid-fluid interface within thetank may change. For example, the position or elevation of thefluid-fluid interface or hypothetical fluid-fluid interface mayincrease. If a barrier or divider is present, the position of thebarrier or divider may change to match or nearly match the change inposition or elevation of the fluid-fluid interface or hypotheticalfluid-fluid interface.

In some embodiments, when the system is neither charging or discharging,the position of the fluid-fluid interface or hypothetical fluid-fluidinterface may remain relatively constant. In some embodiments, a portionof high density fluid may diffuse into the low density fluid, or aportion of low density fluid may diffuse into the high density fluid,which may change the relative amounts of high density fluid or lowdensity fluid, or position or elevation of the fluid-fluid interface, orany combination thereof. In some embodiments, a portion of high densityfluid, or low density fluid, or any combination thereof may be treated,or may undergo a process to recover or remove contaminants, or undergo aprocess to recover or remove constituents of the other fluid, or anycombination thereof, which may result in changes to the position orelevation of a fluid-fluid interface, or may result in changes to therelative volumes or amounts of fluids in the tank, or any combinationthereof.

FIGS. 5-8

FIGS. 5-8 Description

FIGS. 5-8 may show an embodiment with a high elevation reservoir on landand a lower elevation reservoir underwater or under a body of liquid,wherein storage tanks or other storage mechanisms in the higherelevation reservoir and lower elevation reservoir may be configured tostore both high density fluid and low density fluid simultaneous, ifdesired. FIGS. 5-8 may employ a pressure exchange or similar mechanismto exchange power from one fluid to another fluid. The pressureexchanger may be located near the lower elevation reservoir.

In some embodiments, the high density fluid may possess a densitygreater than the density of the liquid body surrounding or adjacent tothe lower elevation reservoir.

In some embodiments, the high density fluid may be at least a portionsoluble in the low density fluid, or the low density fluid may be atleast a portion soluble in the high density fluid.

In some embodiments, FIG. 5-8 may possess a fluid-fluid interface orhypothetical fluid-fluid interface in one or more or any combination ofthe tanks or other storage mechanisms employed comprising the higherelevation reservoir, or lower elevation reservoir, or both.

In some embodiments, FIG. 5-8 may employ a physical barrier or dividerwithin one or more or any combination of the tanks or other storagemechanisms employed comprising the higher elevation reservoir, or lowerelevation reservoir, or both.

Example FIGS. 5-8 Key

Example FIGS. 5-8 Key Label in Figure Description Low Density Lowdensity fluid or lower density fluid may comprise a fluid within anfluid Fluid displacement energy storage system which possesses a densityless than the density of the higher density fluid within the systemunder at least a portion of the operating conditions within the system.For example, some embodiments may employ a low density fluid and a highdensity fluid, wherein energy or power may be stored by displacing atleast a portion of high density fluid in a lower elevation region to ahigher elevation region using a low density fluid transferred from ahigher elevation region., High Density High density fluid or higherdensity fluid may comprise a fluid within an fluid Fluid displacementenergy storage system which possesses a density greater than the densityof the lower density fluid within the system under at least a portion ofthe operating conditions within the system. For example, someembodiments may employ a low density fluid and a high density fluid,wherein energy or power may be stored by displacing at least, a portionof high density fluid in a lower elevation region to a higher elevationregion using a low density fluid transferred from a higher elevationregion. Ocean Ocean may comprise a body of liquid. Ocean may be providedas an example body of liquid, although other bodies of liquid instead ofor in addition to Ocean may be employed, which may include, but are notlimited to, one or more or any combination of the following: ocean, orseas, or lakes, or ponds, or flooded mines, or oil storage, or otherbodies of liquid described herein, or other bodies of liquid known inthe art. Land Land may comprise an at least partially rigid surface orground. In some embodiments, land may comprise a body of solid earth. Insome embodiments, land may comprise a fixed structure or platform in orattached to or embedded in the seafloor. Electricity Electricity maycomprise power stored or generated. ‘Electricity’ may comprise anexample of power stored or generated. Other forms of power or energy maybe stored or generated instead of, or in addition to, ‘Electricity’,which may include, but are not limited to, one or more or anycombination of the following: hydraulic power, or pneumatic power, orkinetic energy, or potential energy, or mechanical energy, or light, orheat, or chemical potential, or magnetism. PX PX may comprise a pressureexchanger or similar device or mechanism. PX may be employed to enablean exchange of at least a portion of pressure or power or energy betweenthe low density fluid and high density fluid, or high density fluid andlow density fluid, or any combination thereof, before the lowerelevation reservoir. In some embodiments, a pressure exchanger mayenable the use of a lower pressure difference rating lower elevationreservoir, which may reduce cost or material requirements. In someembodiments, a pressure exchanger may enable the use of one or morefluids with density greater than the fluids or materials or mediasurrounding or adjacent to the lower elevation reservoir. In someembodiments, a pressure exchanger may enable the elevation of the higherelevation reservoir to be higher than the elevation of the sea level orbody of liquid level, for example, while enabling the lower elevationreservoir to be pressure difference resistant to a lower pressuredifference than the hydraulic head, or to experience a pressuredifference lower than may be presumed based on the hydraulic head, orany combination thereof. 1 ‘1’ may comprise a higher elevationreservoir. In the present figure, ‘1’ may comprise a higher elevationreservoir comprising storage vessels or tanks configured to store lowdensity fluid arid high density fluid. 2 ‘2’ may comprise a pump, orgenerator, or any combination thereof. In the present figure, ‘2’ may bedesigned to pump and/or generate power front low density fluid. ‘2’ mayalso comprise a valve and/or other fluid control or monitoringmechanisms. 3 ‘3’ may comprise a pipe transferring low density fluid.‘3’ may comprise a pipe for transferring low density fluid between thelower elevation region and higher elevation region. ‘3’ may comprise apipe for transferring low density fluid between a pump or generator anda pressure exchanger. 4 ‘4’ may comprise a pipe transferred low densityfluid. ‘4’ may comprise a pipe transferring low density fluid between alower elevation reservoir and a pressure exchanger. ‘4’ may comprise apipe transferring low density fluid between a lower elevation reservoircomprising a tank or storage vessel and a pressure exchanger. 5 ‘5’ maycomprise a lower elevation reservoir. In the present figure, ‘5’ maycomprise a lower elevation reservoir comprising storage vessels or tanksconfigured to store low density fluid and high density fluid. 6 ‘6’ maycomprise a pipe transferring high density fluid. ‘6’ may comprise a pipetransferring high density fluid between a lower elevation reservoir anda pressure exchanger. ‘6’ may comprise a pipe transferring high densityfluid between a lower elevation reservoir comprising a tank or storagevessel and a pressure exchanger. 7 ‘7’ may comprise a pipe transferringhigh density fluid. ‘7’ may comprise a pipe for transferring highdensity fluid between the lower elevation region and higher elevationregion. ‘7’ may comprise a pipe for transferring high density fluidbetween a higher elevation region and a pressure exchanger. ‘7’ maycomprise a pipe for transferring high density fluid between a higherelevation reservoir and a pressure exchanger.

FIG. 5-8 Example Step-by-Step Description

Charging:

Low density fluid may be pumped from a higher elevation reservoir to apressure exchanger, which may be located in or near a lower elevationregion or a lower elevation reservoir

In some embodiments, the pressure of low density fluid entering thepressure exchanger during charging may be greater than the pressure ofhigh density fluid in the lower elevation reservoir or high densityfluid in or near the pressure exchanger. In the pressure exchanger,power may be recovered from the higher pressure, low density fluid andtransferred to the lower pressure, high density fluid, which may resultin the formation of lower pressure, low density fluid and higherpressure, high density fluid. In some embodiments, during charging, thepressure of the low pressure low density fluid may be greater than thepressure of low pressure high density fluid. The resulting high pressurehigh density fluid may be transferred to the higher elevation reservoir,while the low pressure low density fluid may be transferred to the lowerelevation reservoir. In some embodiments, during charging, low densityfluid displaces high density fluid within a lower elevation reservoir.In some embodiments, during charging, high density fluid displaces lowdensity fluid within a higher elevation reservoir.

Discharging:

A valve may be opened, allowing high density fluid in the higherelevation reservoir to displace low density fluid in the lower elevationreservoir. High density fluid may be transferred from a higher elevationreservoir to a pressure exchanger, which may be located in or near alower elevation region or a lower elevation reservoir.

In some embodiments, the pressure of high density fluid entering thepressure exchanger during charging may be greater than the pressure oflow density fluid in the lower elevation reservoir or low density fluidin or near the pressure exchanger. In the pressure exchanger, power maybe recovered from the higher pressure, high density fluid andtransferred to the lower pressure, low density fluid, which may resultin the formation of lower pressure, high density fluid and higherpressure, low density fluid. In some embodiments, during discharging,the pressure of the low pressure high density fluid may be greater thanthe pressure of low pressure low density fluid. The resulting highpressure low density fluid may be transferred to the higher elevationreservoir, while the low pressure high density fluid may be transferredto the lower elevation reservoir. In some embodiments, duringdischarging, high density fluid displaces low density fluid within alower elevation reservoir. In some embodiments, during discharging, lowdensity fluid displaces high density fluid within a higher elevationreservoir.

FIGS. 9-12

FIGS. 9-12 Description

FIGS. 9-12 may show an embodiment with a high elevation reservoirfloating in a water body or other body of liquid and a lower elevationreservoir underwater or under a body of liquid, wherein storage tanks orother storage mechanisms in the higher elevation reservoir and lowerelevation reservoir may be configured to store both high density fluidand low density fluid simultaneous, if desired. FIGS. 9-12 may employ apressure exchange or similar mechanism to exchange power from one fluidto another fluid. The pressure exchanger may be located near the lowerelevation reservoir.

FIGS. 13-16

FIGS. 13-16 Description

FIGS. 13-16 may show an embodiment with a high elevation reservoirfloating in a water body or other body of liquid and a lower elevationreservoir underwater or under a body of liquid, wherein storage tanks orother storage mechanisms in the higher elevation reservoir and lowerelevation reservoir may be configured to store both high density fluidand low density fluid simultaneous, if desired. FIGS. 13-16 may show anembodiment wherein the higher elevation reservoir and/or the lowerelevation reservoir comprise multiple sub-tanks or tanks or storagevessels or storage units. A potential benefit of multiple storage unitsin, for example, a higher elevation reservoir, may include, but are notlimited to, one or more or any combination of the following:minimization of sloshing, or reduction in sloshing and relatedpotentially damaging forces, or greater weight balance, or moreconsistent or stable weight distribution, or greater stability in roughocean conditions and large waves. A potential benefit of multiplestorage units, in, for example, a lower elevation reservoir, mayinclude, but are not limited to, one or more or any combination of thefollowing: easier installation, or lower weight capacity requirement forinstallation, or potential for greater pressure resistance (if desired),or greater redundancy, or a wider range of potential installationvessels, or any combination thereof.

Some versions of the present embodiment may employ a pressure exchanger.

In some embodiments, it may be desirable to store low density fluid andhigh density fluid in a storage unit because, for example, the totalvolume of fluid in the tank may remain relatively consistent, while therelative volume of fluid in the tank may vary or change. If the highdensity fluid and low density fluid are incompressible or practicallyincompressible, the storage unit may be capable of better handlingpressure differences between the interior and exterior of the storageunit, depending on the design of the storage unit.

FIGS. 17-20

FIGS. 17-20 Description

FIGS. 17-20 may show an embodiment with a high elevation reservoirfloating in a water body or other body of liquid and a lower elevationreservoir underwater or under a body of liquid, wherein storage tanks orother storage mechanisms in the higher elevation reservoir may beconfigures to store low density fluid in separate storage units from thehigh density fluid. FIGS. 17-20 may show an embodiment wherein thehigher elevation reservoir and/or the lower elevation reservoir comprisemultiple sub-tanks or tanks or storage vessels or storage units. Apotential benefit of multiple storage units in, for example, a higherelevation reservoir, may include, but are not limited to, one or more orany combination of the following: minimization of sloshing, or reductionin sloshing and related potentially damaging forces, or greater weightbalance, or more consistent or stable weight distribution, or greaterstability in rough ocean conditions and large waves. A potential benefitof multiple storage units, in, for example, a lower elevation reservoir,may include, but are not limited to, one or more or any combination ofthe following: easier installation, or lower weight capacity requirementfor installation, or potential for greater pressure resistance (ifdesired), or greater redundancy, or a wider range of potentialinstallation vessels, or any combination thereof.

In some embodiments, low density fluid or high density fluid may bestored in separate storage units. In some embodiments, if the lowdensity fluid comprises a liquid or solid-liquid and/or the high densityfluid comprises a liquid or solid-liquid, the gas occupying theheadspace of each storage unit may be interconnected or fluidlyconnected between storage units or the headspace of heat storage unitmay be interconnected. For example, when a fluid comprising liquid orsolid-liquid is added to a first storage unit and a fluid comprisingliquid or solid-liquid is being removed from a second storage unit, atleast a portion of gases from the headspace of said first storage unitmay be transferred, or allowed to be transferred or may be flow freely,or any combination thereof to said second storage unit. By enabling gasin the headspace of each storage units to exchange between storageunits, it may enable to the storage reservoir to comprise a closedsystem, or may prevent the fluids in the storage reservoir fromrequiring exposure to outside air or elements, or may minimize theexposure of the high density fluid and/or low density fluid to outsideair or other outside elements, or any combination thereof. In someembodiments, during charging, the volumetry flow rate of low densityfluid exiting the higher elevation reservoir may be about the same orvery similar to the volumetric flow rate of high density fluid enteringthe higher elevation reservoir, which may enable relatively stablepressure during the exchange of headspace gases between storage units.In some embodiments, during discharging, the volumetry flow rate of highdensity fluid exiting the higher elevation reservoir may be about thesame or very similar to the volumetric flow rate of low density fluidentering the higher elevation reservoir, which may enable relativelystable pressure during the exchange of headspace gases between storageunits.

In some embodiments, a gas membrane or liquid membrane or hydrophobicbarrier, or oleophobic barrier, or semi-permeable barrier may be placedin the gas space interconnected between the storage units. For example,in some embodiments, it may be desirable to employ a semi-permeablebarrier in the pipes interconnecting the gas headspace of the storageunits to, for example, enable gas to flow between storage units withprevent liquid or solid-liquid fluids from flowing between storageunits.

FIGS. 21-24

FIG. 21-24 Description

FIGS. 21-24 may show an embodiment with a higher elevation reservoirlocated on land and a lower elevation reservoir located underwater orwithin a body of liquid. In some embodiments, the higher elevationreservoir may be configured to store high density fluid and low densityfluid in separate storage units. In some embodiments, the lowerelevation reservoir may be configured to store high density fluid and/orlow density fluid. In some embodiments, the lower elevation reservoirmay be configured such that when low density fluid is added, highdensity fluid is displaced, and when high density fluid is added, lowdensity fluid is displaced. In some embodiments, a pressure exchanger orsimilar energy recovery or power transfer device or system may beemployed. In some embodiments, a pressure exchanger or similar energyrecovery or power transfer device or system may be employed near a lowerelevation reservoir.

In some embodiments, low density fluid or high density fluid may bestored in separate storage units. In some embodiments, if the lowdensity fluid comprises a liquid or solid-liquid and/or the high densityfluid comprises a liquid or solid-liquid, the gas occupying theheadspace of each storage unit may be interconnected or fluidlyconnected between storage units or the headspace of heat storage unitmay be interconnected. For example, when a fluid comprising liquid orsolid-liquid is added to a first storage unit and a fluid comprisingliquid or solid-liquid is being removed from a second storage unit, atleast a portion of gases from the headspace of said first storage unitmay be transferred, or allowed to be transferred or may be flow freely,or any combination thereof to said second storage unit. By enabling gasin the headspace of each storage units to exchange between storageunits, it may enable to the storage reservoir to comprise a closedsystem, or may prevent the fluids in the storage reservoir fromrequiring exposure to outside air or elements, or may minimize theexposure of the high density fluid and/or low density fluid to outsideair or other outside elements, or any combination thereof. In someembodiments, during charging, the volumetry flow rate of low densityfluid exiting the higher elevation reservoir may be about the same orvery similar to the volumetric flow rate of high density fluid enteringthe higher elevation reservoir, which may enable relatively stablepressure during the exchange of headspace gases between storage units.In some embodiments, during discharging, the volumetry flow rate of highdensity fluid exiting the higher elevation reservoir may be about thesame or very similar to the volumetric flow rate of low density fluidentering the higher elevation reservoir, which may enable relativelystable pressure during the exchange of headspace gases between storageunits.

In some embodiments, a gas membrane or liquid membrane or hydrophobicbarrier, or oleophobic barrier, or semi-permeable barrier may be placedin the gas space interconnected between the storage units. For example,in some embodiments, it may be desirable to employ a semi-permeablebarrier in the pipes interconnecting the gas headspace of the storageunits to, for example, enable gas to flow between storage units withprevent liquid or solid-liquid fluids from flowing between storageunits.

FIGS. 25-28

FIGS. 25-28 Description

FIGS. 25-28 may show an embodiment with a higher elevation reservoirlocated on land and a lower elevation reservoir located on land, orabove the elevation of a body of liquid, or any combination thereof. Insome embodiments, the higher elevation reservoir may be configured tostore high density fluid and low density fluid in separate storageunits. In some embodiments, the lower elevation reservoir may beconfigured to store high density fluid and/or low density fluid. In someembodiments, the lower elevation reservoir may be configured such thatwhen low density fluid is added, high density fluid is displaced, andwhen high density fluid is added, low density fluid is displaced. Insome embodiments, a pressure exchanger or similar energy recovery orpower transfer device or system may be employed. In some embodiments, apressure exchanger or similar energy recovery or power transfer deviceor system may be employed near a lower elevation reservoir.

In some embodiments, low density fluid or high density fluid may bestored in separate storage units. In some embodiments, if the lowdensity fluid comprises a liquid or solid-liquid and/or the high densityfluid comprises a liquid or solid-liquid, the gas occupying theheadspace of each storage unit may be interconnected or fluidlyconnected between storage units or the headspace of heat storage unitmay be interconnected. For example, when a fluid comprising liquid orsolid-liquid is added to a first storage unit and a fluid comprisingliquid or solid-liquid is being removed from a second storage unit, atleast a portion of gases from the headspace of said first storage unitmay be transferred, or allowed to be transferred or may be flow freely,or any combination thereof to said second storage unit. By enabling gasin the headspace of each storage units to exchange between storageunits, it may enable to the storage reservoir to comprise a closedsystem, or may prevent the fluids in the storage reservoir fromrequiring exposure to outside air or elements, or may minimize theexposure of the high density fluid and/or low density fluid to outsideair or other outside elements, or any combination thereof. In someembodiments, during charging, the volumetry flow rate of low densityfluid exiting the higher elevation reservoir may be about the same orvery similar to the volumetric flow rate of high density fluid enteringthe higher elevation reservoir, which may enable relatively stablepressure during the exchange of headspace gases between storage units.In some embodiments, during discharging, the volumetry flow rate of highdensity fluid exiting the higher elevation reservoir may be about thesame or very similar to the volumetric flow rate of low density fluidentering the higher elevation reservoir, which may enable relativelystable pressure during the exchange of headspace gases between storageunits.

In some embodiments, a gas membrane or liquid membrane or hydrophobicbarrier, or oleophobic barrier, or semi-permeable barrier may be placedin the gas space interconnected between the storage units. For example,in some embodiments, it may be desirable to employ a semi-permeablebarrier in the pipes interconnecting the gas headspace of the storageunits to, for example, enable gas to flow between storage units withprevent liquid or solid-liquid fluids from flowing between storageunits.

FIGS. 29-32

FIGS. 29-32 Description

FIGS. 29-32 may show an embodiment with a higher elevation reservoirlocated on land and a lower elevation reservoir located on land, orabove the elevation of a body of liquid, or any combination thereof. Insome embodiments, the higher elevation reservoir may be configured tostore high density fluid and low density fluid in separate storageunits. In some embodiments, the lower elevation reservoir may beconfigured to store to store high density fluid and low density fluid inseparate storage units. In some embodiments, a pressure exchanger orsimilar energy recovery or power transfer device or system may beemployed. In some embodiments, a pressure exchanger or similar energyrecovery or power transfer device or system may be employed near a lowerelevation reservoir.

In some embodiments, low density fluid or high density fluid may bestored in separate storage units. In some embodiments, if the lowdensity fluid comprises a liquid or solid-liquid and/or the high densityfluid comprises a liquid or solid-liquid, the gas occupying theheadspace of each storage unit may be interconnected or fluidlyconnected between storage units or the headspace of heat storage unitmay be interconnected. For example, when a fluid comprising liquid orsolid-liquid is added to a first storage unit and a fluid comprisingliquid or solid-liquid is being removed from a second storage unit, atleast a portion of gases from the headspace of said first storage unitmay be transferred, or allowed to be transferred or may be flow freely,or any combination thereof to said second storage unit. By enabling gasin the headspace of each storage units to exchange between storageunits, it may enable to the storage reservoir to comprise a closedsystem, or may prevent the fluids in the storage reservoir fromrequiring exposure to outside air or elements, or may minimize theexposure of the high density fluid and/or low density fluid to outsideair or other outside elements, or any combination thereof. In someembodiments, during charging, the volumetry flow rate of low densityfluid exiting the higher elevation reservoir may be about the same orvery similar to the volumetric flow rate of high density fluid enteringthe higher elevation reservoir, which may enable relatively stablepressure during the exchange of headspace gases between storage units.In some embodiments, during discharging, the volumetry flow rate of highdensity fluid exiting the higher elevation reservoir may be about thesame or very similar to the volumetric flow rate of low density fluidentering the higher elevation reservoir, which may enable relativelystable pressure during the exchange of headspace gases between storageunits.

In some embodiments, a gas membrane or liquid membrane or hydrophobicbarrier, or oleophobic barrier, or semi-permeable barrier may be placedin the gas space interconnected between the storage units. For example,in some embodiments, it may be desirable to employ a semi-permeablebarrier in the pipes interconnecting the gas headspace of the storageunits to, for example, enable gas to flow between storage units withprevent liquid or solid-liquid fluids from flowing between storageunits.

FIGS. 33-36

FIGS. 33-36 Description

FIGS. 33-36 may show an embodiment with a higher elevation reservoirlocated on land and a lower elevation reservoir located on land, orabove the elevation of a body of liquid, or any combination thereof. Insome embodiments, the higher elevation reservoir may be configured tostore high density fluid and/or low density fluid. In some embodiments,the lower elevation reservoir may be configured to store high densityfluid and/or low density fluid. In some embodiments, the lower elevationreservoir may be configured such that when low density fluid is added,high density fluid is displaced, and when high density fluid is added,low density fluid is displaced. In some embodiments, the higherelevation reservoir may be configured such that when low density fluidis added, high density fluid is displaced, and when high density fluidis added, low density fluid is displaced. In some embodiments, apressure exchanger or similar energy recovery or power transfer deviceor system may be employed. In some embodiments, a pressure exchanger orsimilar energy recovery or power transfer device or system may beemployed near a lower elevation reservoir.

FIGS. 37-40

FIGS. 37-40 Description

FIGS. 37-40 may show an embodiment with a higher elevation reservoirlocated on land or underwater and a lower elevation reservoir locatedunderground. The underground, lower elevation reservoir may comprise,including, but not limited to, one or more or any combination of thefollowing: an underground mine, or a mineshaft, or a retired mine, or anabandoned mine, or an excavated cavern, or an excavated hole, or anunderground cavern, or a salt cavern, or bedded salt cavern, or beddedsalts, or salt dome, or salt dome cavern, or an aquifer, or an abandonedoil well, or an abandoned gas well, or a gas reservoir, or an oilreservoir, or any combination thereof. The present embodiment may enablethe use of nearly entire volume of an underground region or undergroundcavity or an underground space for energy storage. The presentembodiment may advantageously enable pumps, or generators, or turbines,or other moving parts, or any combination thereof to be located on ornear the surface and/or in an accessible and maintainable location,which may enable practical operation and maintenance, and/or while alsoenabling the use of practically incompressible fluids, which may enablehigh round trip energy efficiency. In some embodiments, the lowerelevation reservoir may comprise an open cavity. In some embodiments,the lower elevation reservoir may comprise a closed cavity. In someembodiments, a pipe may be installed by drilling through the ground toan open cavity located underground. In some embodiments, a cavity may becreated underground using drilling fluids, or fluid injection, orexcavation and/or said cavity may function as a lower elevationreservoir. In some embodiments, a tank may be installed underground. Insome embodiments, an underground cavity may function as lower elevationreservoir. In some embodiments, an underground cavity may possesssufficient pressure resistance or resilience to enable the directdisplacement of fluids within the underground cavity and/or for theunderground cavity to experience the maximum hydraulic head pressure. Insome embodiments, a pressure exchanger or similar power recovery orenergy recovery device may be employed near the lower elevationreservoir and/or may reduce the potential pressure exerted on theunderground cavity or lower elevation reservoir.

For example, in some embodiments, the lower elevation reservoir maycomprise a salt cavern, which may be located under land, or under a bodyof water. For example, the lower elevation reservoir may comprise a saltcavern. In some embodiments, the low density fluid may comprise ahydrocarbon or hydrogen. In some embodiments, the high density fluid maycomprise a brine. Power or energy may be stored by pumping a low densityfluid into the lower elevation reservoir comprising a salt cavern,displacing high density fluid comprising brine from the lower elevationreservoir into the higher elevation reservoir. Power may be generated byallowing the high density fluid comprising brine in the higher elevationreservoir to displace the low density fluid from the lower elevationreservoir into the higher elevation reservoir. In some embodiments,power may be stored or generated using pumps, or turbines, or pressureexchangers, or other mechanical equipment located above ground or nearthe higher elevation reservoir. In some embodiments, the higherelevation reservoir may comprise a land based structure. In someembodiments, the higher elevation reservoir may comprise a floatingstructure. In some embodiments, the higher elevation reservoir maycomprise an underwater structure.

FIGS. 41-44

FIGS. 41-44 Description

FIGS. 37-40 may show an embodiment with a higher elevation reservoirlocated on land at an elevation substantially greater than the body ofwater or body of liquid and a lower elevation reservoir located underthe body of water or body of liquid. In some embodiments, the hydraulicpressure exerted on the inside of the lower elevation reservoir may begreater than the hydrostatic pressure of the body of water or body ofliquid at the depth of the lower elevation reservoir. In someembodiments, the lower elevation reservoir may be designed to withstanda pressure difference between the internal and external pressures of thelower elevation reservoir greater than or equal to the pressuredifference between the hydrostatic head pressure of the high densityfluid in the system minus the hydrostatic heat pressure of the body ofwater or body of liquid at or near the depth of the lower elevationreservoir.

FIGS. 45-48

FIGS. 45-48 Description

FIGS. 45-48 may show an embodiment with a higher elevation reservoirlocated on land at an elevation substantially greater than the body ofwater or body of liquid and a lower elevation reservoir located underthe body of water or body of liquid, and/or further comprising apressure exchanger or other power recovery or energy recovery device orsystem. In some embodiments, said pressure exchanger may be located nearthe lower elevation reservoir. In some embodiments, said pressureexchanger may recover pressure or power in excess of the hydrostaticpressure head of the body of water or body of liquid adjacent to thelower elevation reservoir at the depth of the lower elevation reservoir,and provide said recovered pressure or power to the opposing fluid. Byemploying a pressure exchanger, the lower elevation reservoir may beconstructed to withstand lower pressure differences and/or may be lessexpensive to construct and/or may be less expensive or easier to installcompared to a lower elevation reservoir designed to withstand the fullhydrostatic head pressure difference between the high density fluid andthe body of water or body of other liquid adjacent to the lowerelevation reservoir near the depth of the lower elevation reservoir.

FIGS. 49-52

FIGS. 49-52 Description

FIGS. 49-52 may show an embodiment with a higher elevation reservoirlocated on land at an elevation substantially greater than the body ofwater or body of liquid and a lower elevation reservoir located underthe body of water or body of liquid, and/or further comprising apressure exchanger or other power recovery or energy recovery device orsystem. The present embodiment may employ a higher elevation reservoirconfigured to store high density fluid and low density fluid in the samestorage units or storage tanks. The present embodiment may employ ahigher elevation reservoir configured to store high density fluid andlow density fluid in separate storage units or storage tanks. In thepresent embodiment, the pressure exchanger may be located on land at anelevation lower than the elevation of the higher elevation reservoir andhigher than the elevation of the lower elevation reservoir. In someembodiments, the pressure exchanger may be located near sea level, ornear the water surface level of the body of water, or near the surfacelevel of a body of water to enable the recovery of pressure or powerassociated with the elevation change or elevation difference above thebody of water or body of liquid surface level, while preventing thelower elevation reservoir from experiencing the additional hydrostaticpressure resulting from the elevation change or elevation differenceabove the body of water or body of liquid surface level. Additionally,by locating the pressure exchanger on land, the pressure exchanger maybe more accessible and/or easier to maintain, if needed.

FIGS. 53-56

FIGS. 53-56 Description

FIGS. 53-56 may show an embodiment with a higher elevation reservoirlocated on land at an elevation substantially greater than the body ofwater or body of liquid and a lower elevation reservoir located underthe body of water or body of liquid, and/or further comprising apressure exchanger or other power recovery or energy recovery device orsystem. The present embodiment may employ a higher elevation reservoirconfigured to store high density fluid and low density fluid in separatestorage units or storage tanks. In some embodiments, while the highdensity fluid and low density fluid in the higher elevation reservoirmay be stored in separate storage units or storage tanks, the headspacegas between the storage units or storage tanks may be interconnectedbetween storage units or storage tanks.

FIGS. 57-60

FIGS. 57-60 Description

FIGS. 53-56 may show an embodiment with a higher elevation reservoirlocated underwater or under a body of water or under a body of liquid,and a lower elevation reservoir located under the body of water or bodyof liquid at an elevation substantially lower than the elevation of thehigher elevation reservoir and/or further comprising a pressureexchanger or other power recovery or energy recovery device or system.

The present embodiment may be useful for offshore windfarms, or floatingsolar farms, or subsea cables, or other offshore infrastructure whichmay be located near an underwater shelf, such as a continental shelf.The present embodiment may be useful for applications where shallowwater depths may be in relatively close proximity to deep water depthsnear a subsea slope or shelf.

FIGS. 61-64

FIGS. 61-64 Description

FIGS. 61-64 may show an embodiment where the pump and/or generator islocated near the lower elevation reservoir. FIGS. 61-64 may show anembodiment where the pump and/or generator mechanically interacts with,or directly interacts with, or pumps, or generates power from, or anycombination thereof the high density fluid.

In some embodiments, the pump and/or generator may be located near thelower elevation reservoir and may be fluidly connected to the highdensity fluid. In some embodiments, it may be desirable for the lowdensity fluid to possess the lowest density practical. For example, insome embodiments, the low density fluid may comprise the vapor phase ofthe high density fluid. For example, in some embodiments, the lowdensity fluid may comprise a gas at a pressure similar to or near thepressure of the ambient pressure outside or adjacent to the lowerelevation reservoir, or higher elevation reservoir, or any combinationthereof. For example, the low density fluid may comprise, including, butnot limited to, one or more or any combination of the following: air, ornitrogen, or water vapor, or high density fluid vapor pressure, or highdensity fluid vapor phase, or argon, or hydrogen, or ammonia, ormethane, or ethane, or propane, or a liquid, or helium, or butane, orpentane, or oxygen, or fluorocarbon gas phase, or refrigerant gas phase,or sulfurous compound gas phase, or any combination thereof. Forexample, the high density fluid may comprise, including, but not limitedto, one or more or any combination of the following: water, or brinewater, or aqueous solution, or solid-liquid mixture, or fluorocarbonliquid phase, or refrigerant liquid phase, sulfurous compound liquid, orsulfur dioxide liquid, or molten sulfur, or liquid sulfur, or moltensalt, or liquid salt, or mercury, or gallium, or liquid metal, or liquidmetal alloy, or nitric acid, or sulfuric acid, or phosphoric acid, oracid, or base, or high density liquid, or any combination thereof.

In some embodiments, the low density fluid may be at a pressuresignificantly below the hydraulic head or column head pressure of thehigh density fluid near the pump or generator near the lower elevationreservoir. For example, the low density fluid may be at a pressure nearthe ambient pressure adjacent to the lower elevation reservoir, or highelevation reservoir, or any combination thereof, or the low densityfluid may be at a pressure near the vapor pressure of the high densityfluid, or any combination thereof. In some embodiments, the pressure ofinside the lower elevation reservoir and the higher elevation reservoirmay be about the same as the pressure of the low density fluid. In someembodiments or the present embodiment, the greatest pressure in thesystem may exist near the pump or turbine or generator. In someembodiments or the present embodiment, the greatest pressure in thesystem may exist near the pump or turbine or generator outlet or inletconnecting to the pipe which transfers high density fluid between thelower elevation region and higher elevation region.

In some embodiments, during charging of the energy storage system, highdensity fluid may be pumped or transferred from a lower elevationreservoir to a higher elevation reservoir, wherein, for example, thehigh density fluid entering the higher elevation reservoir may displacethe low density fluid in the higher elevation reservoir and/or saiddisplaced low density fluid may be transferred to the lower elevationreservoir, wherein, for example, the low density fluid entering thelower elevation reservoir may displace the high density fluid in thelower elevation reservoir.

In some embodiments, during discharging of the energy storage system,high density fluid may transferred from a higher elevation reservoir toa lower elevation reservoir, through a generator or turbine, into thelower elevation reservoir, wherein, for example, the high density fluidentering the lower elevation reservoir may displace the low densityfluid in the lower elevation reservoir and/or said displaced low densityfluid may be transferred to the higher elevation reservoir, wherein, forexample, the low density fluid entering the higher elevation reservoirmay displace the high density fluid in the higher elevation reservoir.

Energy may be stored in the gravitational potential energy of a highdensity fluid in a reservoir or region which is at a higher elevationthan another interconnected reservoir or region.

In some embodiments, the low density fluid and/or high density fluid maybe transferred between the lower elevation reservoir and the higherelevation reservoir by means of pipes.

In some embodiments, the volume of high density fluid entering areservoir may be about the same as the volume of low density fluidexiting a reservoir. In some embodiments, the volume of low densityfluid entering a reservoir may be about the same as the volume of highdensity fluid exiting a reservoir.

In some embodiments, the energy storage system may comprise a closedsystem, wherein liquids, or gases, or solids, or any combination thereofremain within the system and/or practically or mechanically isolatedfrom contact with the outside environment during regular or normaloperation. In some embodiments, the exchange or transfer of low densityfluid between the higher elevation reservoir and lower elevationreservoir and vise versa may enable the system to be a closed system.

Some embodiments may be a beneficial energy storage system for land orwater based energy storage applications. Some embodiments may enable theuse of a high density fluid with a vapor pressure, while, during normaloperation, minimizing or eliminating possible high density fluid lossesdue to evaporation. Some embodiments may enable the use of a highdensity fluid which may be harmful for the environment. Some embodimentsmay enable the use of a hygroscopic high density fluid. Some embodimentsmay prevent or eliminate potential biofouling, or scaling, ordegradation, or any combination thereof due to, for example, minimal orpractically no exposure of low density fluid and/or high density fluidto air or outside environment during normal operation. Some embodimentsmay prevent high density fluid and/or low density fluid from beingcontaminated by rain, or dirt, or dust, or insects, or debris, or anycombination thereof during normal operation. Some embodiments mayimprove the longevity of equipment and/or high density fluid and/or lowdensity fluid due to being capable of operating as a closed systemduring normal operations. Some embodiments may prevent evaporation andrelated losses of high density fluid or low density fluid due to beingcapable of operating as a closed system during normal operations.

In some embodiments, the low density fluid may comprise an inert gas,such as nitrogen gas, or argon, or water vapor, or any combinationthereof.

For example, the present embodiment may employ water or an aqueoussolution as the high density fluid. For example, the ability to operateas a closed system during normal operations may prevent, or greatlyreduce the risk or rate of biofouling. Due to the ability to operate asa closed system during normal operations, the water or aqueous solutionmay be deoxygenated, or treated, or deionized, or any combinationthereof, which may greatly reduce or prevent corrosion, or degradation,or scaling.

For example, the present embodiment may employ a salt-water solution ora concentrated brine as the high density fluid. A salt water solution orconcentrated brine may be deoxygenated or treated, preventing corrosion.Concentrated salt water brine may not be diluted or contaminated due tooperating in a closed system during normal operations.

For example, the present embodiment may employ liquid sulfur as a highdensity fluid. Liquid sulfur has a viscosity of about 8 cP around 140degrees Celsius, which is a low viscosity and a pumpable viscosity.Liquid sulfur may be low cost, ranging from $35 to $150 per metric tonbased on recent commodity prices. Sulfur may be an abundant commodityand with many uses and applications. Liquid sulfur has a viscosity ofabout 8 cP around 140 degrees Celsius, which may be a low viscosityand/or a pumpable viscosity. The density of liquid sulfur is about 2kg/L, or about 2 times greater density than water. Embodiments employingliquid sulfur and/or other above ambient temperature fluids may employinsulated tank and/or insulated pipes and/or insulated other equipmentand/or may employ a heater to maintain the temperature of the liquidsulfur in the system. In some embodiments, heating may reduce the roundtrip efficiency, however, due to the large volumes and mass of liquidsulfur in the system, the relative reduction in efficiency from theheating may be less than a 1%, or 3%, or 5%, or 10%, or 15%, or 20%,round trip efficiency penalty. The present embodiment may enable the useof liquid sulfur due to, for example, the ability to operate as a closedsystem.

For example, the present embodiment may employ phosphoric acid as a highdensity fluid. Phosphoric acid is a strategically important commoditydue to its important role in fertilizer and it scarcity. There may be astrategic or beneficial value in nations possessing a stockpile orreserve of phosphoric acid to ensure resilience in case of supply chaindisruptions or manufacturing disruptions. Some embodiments may enablesimultaneous or productive use of said stockpile or reserve by employingsaid stockpile or reserve phosphoric acid as a high density fluid in anenergy storage system. Phosphoric acid possesses a density of about 1.88kg/L, or about 1.88 times the density of water. 85 wt % aqueous solutionof phosphoric acid in water possesses a viscosity less than 10 cP atabout 20 degrees Celsius.

For example, the present embodiment may employ Urea-Ammonium Nitrate(UAN) solution as a high density fluid. Phosphoric acid is astrategically important commodity due to its important role infertilizer. There may be a strategic or beneficial value in nationspossessing a stockpile or reserve of UAN solution to ensure resiliencein case of supply chain disruptions or manufacturing disruptions. Someembodiments may enable simultaneous or productive use of said stockpileor reserve by employing said stockpile or reserve UAN solution as a highdensity fluid in an energy storage system. UAN solution possesses adensity of about 1.32 kg, or about 1.32 times the density of water. UANsolution possesses viscosity less than about 10 cP at about 20 degreesCelsius.

Note: The present embodiment may be located on land, or under water, orany combination thereof.

Example FIGS. 61-64 Key

Example FIGS. 61-64 Key Label Description 1 ‘1’ may comprise a higherelevation reservoir. ‘1’ may comprise a higher elevation reservoircomprising a storage unit or comprising storage units configured tostore high density fluid and low density fluid. 2 ‘2’ may comprise apipe for transferring low density fluid between the lower elevationreservoir and higher elevation reservoir. 3 ‘3’ may comprise a lowerelevation reservoir. ‘3’ may comprise a lower elevation reservoircomprising a storage unit or comprising storage units configured tostore high density fluid and low density fluid. 4 ‘4’ may comprise apipe for transferring high density fluid between the lower elevationreservoir and a pump, or turbine, or generator, or any combinationthereof. 5 ‘5’ may comprise a pump, or turbine, or generator, or anycombination thereof. ‘5’ may be located near the lower elevationreservoir or in the lower elevation region in the present embodiment. 6‘6’ may comprise a pipe for transferring high density fluid between thepump, or turbine, or generator, or any combination thereof and thehigher elevation reservoir.

FIGS. 83-90

FIGS. 83-90 Description

FIGS. 83-86 may show an embodiment with a lower elevation reservoirlocated underground under a body of water. FIG. 83-86 may show anembodiment where the lower elevation reservoir comprises a cavity orcavern beneath the seabed or a subterranean cavern under the seabed, orunder a body of water, or under land near, or under the floor of a bodyof water.

FIGS. 83-90 may show an embodiment with a floating higher elevationreservoir and a lower elevation reservoir located underground, orbeneath the seabed underground, or under a body of water, or anycombination thereof. The underground, lower elevation reservoir maycomprise, including, but not limited to, one or more or any combinationof the following: an underground cavern, or a salt cavern, or beddedsalt cavern, or bedded salts, or salt dome, or salt dome cavern, or anaquifer, or an abandoned oil well, or an abandoned gas well, or a gasreservoir, or an oil reservoir, or an underground mine, or a mineshaft,or a retired mine, or an abandoned mine, or an excavated cavern, or anexcavated hole, or any combination thereof. The present embodiment mayenable the use of nearly entire volume of an underground region orunderground cavity or an underground space for energy storage. Thepresent embodiment may advantageously enable pumps, or generators, orturbines, or other moving parts, or any combination thereof to belocated on or near the surface and/or in an accessible and maintainablelocation, which may enable practical operation and maintenance, and/orwhile also enabling the use of practically incompressible fluids, whichmay enable high round trip energy efficiency. In some embodiments, thelower elevation reservoir may comprise an open cavity. In someembodiments, the lower elevation reservoir may comprise a closed cavity.In some embodiments, a pipe may be installed by drilling through theground to an open cavity located underground. In some embodiments, acavity may be created underground using drilling fluids, or fluidinjection, or excavation and/or said cavity may function as a lowerelevation reservoir. In some embodiments, a cavity may be pre-existing.In some embodiments, a cavity may be constructed using methods forconstructing cavities known in the art. In some embodiments, a cavitymay be constructed using systems and methods for constructing saltcaverns or subterranean salt storage. In some embodiments, a tank may beinstalled underground. In some embodiments, an underground cavity mayfunction as lower elevation reservoir. In some embodiments, anunderground cavity may possess sufficient pressure resistance orresilience to enable the direct displacement of fluids within theunderground cavity and/or for the underground cavity to experience themaximum hydraulic head pressure associated with, for example, elevationdifferences, or fluid densities, or gravity. In some embodiments, apressure exchanger or similar power recovery or energy recovery devicemay be employed near the lower elevation reservoir and/or may reduce thepotential pressure exerted on the underground cavity or lower elevationreservoir.

For example, in some embodiments, the lower elevation reservoir maycomprise a salt cavern, which may be located under land, or under a bodyof water, or any combination thereof. For example, the lower elevationreservoir may comprise a salt cavern. In some embodiments, the lowdensity fluid may comprise a hydrocarbon or hydrogen. In someembodiments, the high density fluid may comprise a brine. Power orenergy may be stored by pumping a low density fluid into the lowerelevation reservoir comprising a salt cavern, displacing high densityfluid comprising brine from the lower elevation reservoir into thehigher elevation reservoir. Power may be generated by allowing the highdensity fluid comprising brine in the higher elevation reservoir todisplace the low density fluid from the lower elevation reservoir intothe higher elevation reservoir. In some embodiments, power may be storedor generated using pumps, or turbines, or pressure exchangers, or othermechanical equipment located above ground or near the higher elevationreservoir. In some embodiments, the higher elevation reservoir maycomprise a land based structure. In some embodiments, the higherelevation reservoir may comprise a floating structure. In someembodiments, the higher elevation reservoir may comprise an underwaterstructure.

Subsea subterranean salt formations are known in many geographically andeconomically favorable locations in the world, which include, but arenot limited to the Gulf of Mexico and offshore Europe.

Example Exemplary Embodiments

(1) A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto return to the first storage reservoir; and

wherein the first fluid is a liquid.

(2) The system of example exemplary embodiment 1 wherein the highdensity fluid is soluble in the low density fluid.

(3) The system of example exemplary embodiment 1 wherein the low densityfluid and high density fluid are stored within the same storage unitswithin at least the second storage reservoir.

(4) The system of example exemplary embodiment 3 wherein the low densityfluid is located above the high density fluid within a storage unit.

(5) The system of example exemplary embodiment 3 wherein the low densityfluid is separate from the high density fluid by a fluid-fluidinterface.

(6) The system of example exemplary embodiment 3 wherein the low densityfluid is separate from the high density fluid by a chemocline orchemocline layer.

(7) The system of example exemplary embodiment 3 wherein the low densityfluid is separate from the high density fluid by a physical divider.

(8) The system of example exemplary embodiment 7 wherein the physicaldivider occupies at least 50% of the surface area or cross sectionalarea otherwise occupied by a fluid-fluid interface.

(9) The system of example exemplary embodiment 7 wherein the physicaldivider adjusts elevation to follow the change in elevation of thefluid-fluid interface or hypothetical fluid-fluid interface.

(10) The system of example exemplary embodiment 7 wherein the physicaldivider is floating.

(11) The system of example exemplary embodiment 7 wherein the density ofthe physical divider is greater than the density of the low densityfluid and less than the density of the high density fluid.

(12) The system of example exemplary embodiment 1 wherein the highdensity fluid and low density fluid are stored in the same storage unitswithin the first storage reservoir and the second storage reservoir.

(13) The system of example exemplary embodiment 2 wherein at least aportion of high density fluid mixes with at least a portion of lowdensity fluid.

(14) The system of example exemplary embodiment 13 wherein at least aportion of high density fluid is removed from the low density fluid by aseparation process.

(15) The system of example exemplary embodiment 14 wherein saidseparation process is selected from reverse osmosis, or forward osmosis,or distillation, or evaporation, or gravitational separation, ordecanting, or coalescing, or centrifuge, or filtration, orcryodesalination, or freeze desalination, solventing out, orprecipitation, or extraction, or extractive distillation.

(16) The system of example exemplary embodiment 2 wherein at least aportion of low density fluid mixes with at least a portion of highdensity fluid.

(17) The system of example exemplary embodiment 16 wherein at least aportion of low density fluid is removed from the high density fluid by aseparation process.

(18) The system of example exemplary embodiment 17 wherein saidseparation process is selected from reverse osmosis, or forward osmosis,or distillation, or evaporation, or electrodialysis, or gravitationalseparation, or decanting, or coalescing, or centrifuge, or filtration,or cryodesalination, or freeze desalination, solventing out, orprecipitation, or extraction, or extractive distillation.

(19) The system of example exemplary embodiment 2 wherein the lowdensity fluid comprise water and the high density fluid comprises brine.

(20) The system of example exemplary embodiment 1 wherein the highdensity fluid and low density fluid are stored in separate storage unitswithin at least the first storage reservoir.

(21) The system of example exemplary embodiment 20 wherein the highdensity fluid and low density fluid comprise liquids.

(22) The system of example exemplary embodiment 21 wherein the headspaceof each storage unit within a reservoir is interconnected such that gasin the head space of the storage units is transferred from storage unitswhere liquid is entering to storage units where liquid is exiting.

(23) The system of example exemplary embodiment 22 wherein asemi-permeable barrier is employed to allow the transfer of gas whilepreventing the transfer of liquid between storage units with differentliquids.

(24) The system of example exemplary embodiment 1 wherein the firststorage reservoir is located underwater.

(25) The system of example exemplary embodiment 1 wherein the firststorage reservoir is at an elevation reservoir at an elevation greaterthan the elevation of the surface of the body of water.

(26) The system of example exemplary embodiment 1 wherein the firststorage reservoir comprises a floating structure,

(27) The system of example exemplary embodiment 1 further comprising apressure exchanger.

(28) The system of example exemplary embodiment 27 wherein the pressureexchanger is located at an elevation less than the elevation of thefirst storage reservoir and greater than or equal to the elevation ofthe second storage reservoir.

(29) The system of example exemplary embodiment 1 wherein the lowdensity fluid or high density fluid comprises desalinated water.

(30) The system of example exemplary embodiment 1 wherein the lowdensity fluid or high density fluid comprises seawater, or treatedseawater.

(31) The system of exemplary embodiment 1 wherein the low density fluidcomprises a hydrocarbon, or hydrogen, or any combination thereof.

(32) The system of exemplary embodiment 1 wherein the second storagereservoir comprises an underground cavern

(33) The system of exemplary embodiment 1 wherein the second storagereservoir comprises an underwater and underground cavern

wherein said underground cavern is located under the seabed

(34) The system of exemplary embodiment 1 wherein the second storagereservoir comprises a salt cavern

(35) The system of exemplary embodiment 1 wherein the low density fluidcomprises a hydrocarbon selected from butane, or propane and the highdensity fluid comprises a brine

Notes

Note: Some embodiments may employ a reservoir, such as a storage vesselor tank, which may store a high density liquid and/or a low densityliquid. In some embodiments, the high density liquid may be soluble inthe low density liquid, or the low density liquid may be soluble in thehigh density liquid, or any combination thereof. In some embodiments,the reservoir may store high density liquid and low density liquid inthe same tank or vessel and the high density liquid may be soluble inthe low density liquid, or the low density liquid may be soluble in thehigh density liquid, or any combination thereof. In some embodiments, atank or vessel may store low density liquid and high density liquid,wherein the low density liquid in the tank may be positioned above, orlocated above, or floating above the high density liquid. In someembodiments, the low density liquid in the tank may comprise a separatelayer from the high density liquid, and/or wherein a liquid-liquidinterface exists between the low density liquid and the high densityliquid in the tank. In some embodiments, a transition layer may existbetween the low density liquid layer and the high density liquid layer,wherein the concentration of low density liquid or high density liquidvaries within the transition layer, and/or wherein the concentration ofthe low density liquid in the transition layer is greater the closer tothe low density liquid layer and the concentration of the high densityliquid in the transition layer is greater the closer to the high densityliquid layer. In some embodiments, the low density liquid may comprisefreshwater or water with a relatively low dissolved salt or soluteconcentration and the high density liquid may comprise a brine or anaqueous solution with a relatively high dissolved salt or soluteconcentration. In some embodiments, a transition layer may exist betweenthe freshwater low density liquid layer and the brine high densityliquid layer, wherein the concentration of dissolved salt or solutevaries within the transition layer, and/or wherein the concentration ofthe dissolved salt or dissolved solute in the transition layer is lowerthe closer to the freshwater low density liquid layer and theconcentration of the dissolved salt or dissolved solute is greater thecloser to the high density liquid layer. In some embodiments, one ormore diffusers may be employed in the vessel or tank to, for example,enable the addition or removal of low density liquid or high densityliquid or both while minimizing turbulence or mixing of the layers. Saiddiffusers may include, but are not limited to, diffusers similar tothose employed in large chilled water thermal storage tanks, which inchilled water applications may involve minimizing the mixing between awarm water layer and a cold water layer when warm water or cold water orboth is removed from the tank.

Note: In some embodiments, a floating or suspended barrier or plate orphysical divider may be located between the low density liquid layer andthe high density liquid layer. If said physical divider is floating, itmay be desirable for said physical divider to comprise a material orcombination of materials and/or may have an overall density less thanthe density of the high density liquid and greater than the density ofthe low density liquid. If said physical divider is mechanically placed,it may be desirable

Note: In some embodiments, the high density fluid may be soluble in thelow density fluid, or the low density fluid may be soluble in the highdensity fluid, or any combination thereof. In some embodiments, highdensity fluid and/or low density fluid may mix. In some embodiments,said mixing of the high density fluid and/or low density fluid may beinadvertent. In some embodiments, said mixing of the high density fluidand/or low density fluid may be an aspect of the design or within thenature of the process. For example, some mixing of the high densityfluid and/or low density fluid may occur in, including, but not limitedto, one or more or any combination of the following: in a pressureexchanger, or in the higher elevation reservoir, or in the lowerelevation reservoir, or in another location in the energy storagesystem, or any combination thereof. In some embodiments, the rate ofmixing between the low density fluid and high density fluid may beunpredictable. In some embodiments, the rate of mixing between the lowdensity fluid and high density fluid may be predictable. In someembodiments, mixing of the low density fluid and high density fluid maynot result in a material dissolution of low density fluid into the highdensity fluid, or high density fluid into the low density fluid, or anycombination thereof. In some embodiments, mixing of the low densityfluid and high density fluid may result in a material dissolution of lowdensity fluid into the high density fluid, or high density fluid intothe low density fluid, or any combination thereof. In some embodiments,the high density fluid may be regenerated or purified, or the lowdensity fluid may be regenerated or purified, or any combinationthereof. In some embodiments, regeneration or purification may beconducted in a manner which is batch, or semi-batch, or continuous, orany combination thereof. For example, the high density fluid may beregenerated or purified, or the low density fluid may be regenerated orpurified, or any combination thereof using, for example, including, butnot limited to, one or more or any combination of the following:

In some embodiments, regeneration or purification may involve treating,or concentrating, or purifying only a portion of the high density fluidor the low density fluid.

Reverse Osmosis or Nanofiltration or Membrane Based Process

For example, in some embodiments, the high density fluid may comprise asalt brine and the low density fluid may comprise freshwater. In someembodiments, a portion of high density fluid comprising a salt brine maymix with a portion of low density fluid comprising freshwater, which mayresult in the freshwater comprising a higher salinity or saltconcentration and/or the brine comprising a lower salinity or saltconcentration. In some embodiments, at least a portion of the lowdensity comprising freshwater with a higher salinity may be transferredinto a reverse osmosis desalination system as the feed solution, forminga salt solution retentate and freshwater with a lower salinity. In someembodiments, the freshwater with a lower salinity may be returned to ortransferred to or mixed with the low density fluid comprisingfreshwater. In some embodiments, the retentate may be furtherconcentrated, using, for example, including, but not limited to, one ormore or any combination of the following: high pressure reverse osmosis,or high pressure nanofiltration, or DTRO, or forward osmosis, orosmotically assisted reverse osmosis, or distillation, or membranedistillation, or evaporation, or salting out, or solventing out, orcryodesalination, or zero liquid discharge techniques. If or when saidfurther concentrated retentate possesses a salt concentration, orsalinity, or osmotic pressure, or any combination thereof near, or equalto, or greater than the high density fluid, said further concentratedretentate may be transferred to or mixed with the high density fluidcomprising salt brine.

Forward Osmosis or Dilution or any Combination Thereof

For example, in some embodiments, the low density fluid may comprisesalt water with a lower salinity or salt concentration than a highdensity fluid, which may comprise a salt brine. For example, in someembodiments, the salt concentration or osmotic pressure of the lowdensity fluid may be designed to be similar to, or less than, or greaterthan the salinity or osmotic pressure of ocean water. If or when thesalinity or osmotic pressure of at least a portion of low density fluidincreases due to mixing with the high density fluid comprising saltbrine, it may be desirable to add water or other dilutant to the lowdensity fluid. In some embodiments, the excess volume of low densityfluid due to the dilution may be discharged into the ocean if, forexample, the low density fluid comprises the same or similar compositionas ocean water. In some embodiments, seawater or treated seawater maycomprise a dilutant.

In some embodiments, seawater or treated seawater may be employed as awater source or feed solution in a forward osmosis process. For example,the low density fluid may be employed as a draw solution, and/or waterfrom the feed solution comprising seawater or treated seawater travelacross or through the membrane into the draw solution, which mayeffectively enable the addition of water or freshwater to the lowdensity fluid from a seawater or other saline source. In someembodiments, pressure may be applied to the feed solution to facilitatethe transfer of water from the feed solution to the draw solution.

In some embodiments, it may be desirable to concentrate the brine and/oradd any makeup salt or brine solution from any potential losses.

Concentrating using evaporation, or distillation, or membranedistillation, or membrane based process, or any combination thereof

In some embodiments, if brine is employed as a high density fluid, itmay be desirable to concentrate the brine or remove water from thebrine. In some embodiments, concentrating of the brine or removing waterfrom the brine may comprise concentrating or removing water from atleast a portion of the brine using, for example, including, but notlimited to, one or more or any combination of the following:evaporation, or distillation, or membrane distillation, or membranebased process, or freeze desalination, or cryodesalination, orsolventing out, or precipitation.

Note: Some embodiments may comprise a higher elevation reservoir and alower elevation reservoir. Energy may be stored by displacing highdensity fluid from a lower elevation reservoir into a higher elevationreservoir by pumping a low density fluid pumped from a higher elevationreservoir into a lower elevation reservoir. Energy may be generated bydisplacing lower density fluid from the lower elevation reservoirthrough a generator, generating power, and into the higher elevationreservoir by allowing higher density from the higher elevation reservoirto transfer into the lower elevation reservoir. In some embodiments, thehigher elevation reservoir may be floating, or may be on land, or acombination thereof.

In some embodiments, the higher elevation reservoir may comprise storagereservoirs for high density fluid and storage reservoirs for low densityfluid, wherein the storage reservoirs for high density fluid arephysical separate from the storage reservoirs for low density fluid.

In some embodiments, the lower elevation reservoir may comprise storagereservoirs for high density fluid and storage reservoirs for low densityfluid, wherein the storage reservoirs for high density fluid arephysical separate from the storage reservoirs for low density fluid.

In some embodiments, the higher elevation reservoir may comprise astorage reservoir designed for both high density fluid and low densityfluid, wherein high density fluid and low density fluid may be stored inthe same vessel or reservoir simultaneously. For example, the highdensity fluid and low density fluid may be stored in the same vessel andat least partially separated by a density stratification. For example,the high density fluid and low density fluid may be stored in the samevessel and at least partially separated by a physical divider.

In some embodiments, the lower elevation reservoir may comprise astorage reservoir designed for both high density fluid and low densityfluid, wherein high density fluid and low density fluid may be stored inthe same vessel or reservoir simultaneously. For example, the highdensity fluid and low density fluid may be stored in the same vessel andat least partially separated by a density stratification. For example,the high density fluid and low density fluid may be stored in the samevessel and at least partially separated by a physical divider.

In some embodiments, the higher elevation reservoir may be stable or maybe stationary.

In some embodiments, the higher elevation reservoir may be mobile, ormove positions. In some embodiments, the higher elevation reservoir maybe mobile or move positions when in direct or indirect contact with awave of a sufficient size in a body of water, which may involve, forexample, the higher elevation reservoir rising and falling in thepresence of said waves, which may be similar to a ship or oceangoingvessel. In some embodiments, substantial movement of a reservoir mayresult in movement or mixing or sloshing of the high density fluidand/or low density fluid. In embodiments with a reservoir withsubstantial sloshing and/or high density fluid soluble in low densityfluid, it may be desirable for the high density fluid to be stored in aphysically separate tank or reservoir from the low density liquid.

In some embodiments, the higher elevation reservoir may comprisephysically separate storage for low density fluid and high densityfluid, while the lower elevation reservoir may comprise storage of lowdensity fluid and high density fluid in the same vessels or other formof reservoir.

In some embodiments, the low density fluid may comprise a low saltconcentration aqueous solution, such as seawater or purified seawater orionic solution with similar concentration or osmotic pressure asseawater, and the high density fluid may comprise a brine, which maycomprise a greater ionic concentration or osmotic pressure than said lowsalt concentration aqueous solution.

In some embodiments, mobile reservoirs or reservoirs prone to sloshingmay contain baffles or physical structures within the tanks which mayminimize sloshing and/or may prevent potentially damaging internal waveaccumulation.

In some embodiments, the higher elevation reservoir may comprise afloating structure with storage tanks for low density fluidnon-contiguously separate from storage tanks for high density fluid. Insome embodiments, the high density fluid tanks and low density fluidtanks may be positioned in or on a floating structure in a configurationwhich may facilitate stability regardless of the state of charge of theenergy storage system, or the relative amount of high density fluid inthe higher elevation region, or the relative amount of low density fluidin the higher elevation region, or any combination thereof. For example,in some embodiments, in some embodiments, high density fluid storagetanks may be located between low density fluid tanks, or low densityfluid tanks may be located between high density fluid tanks, or anycombination thereof. For example, in some embodiments, at least aportion of the outside of a floating structure may store high densityfluid, while at least a portion of the inside of a floating structuremay storage low density fluid.

Note: In some embodiments, the energy storage system may be entirely onland. For example, in some embodiments, the higher elevation reservoirmay be located on land and lower elevation reservoir may be located onland.

For example, some embodiments may comprise a higher elevation reservoirand a lower elevation reservoir, wherein the higher elevation reservoirpossesses an elevation higher than the lower elevation reservoir and maybe located on land and the lower elevation reservoir possesses anelevation lower than the higher elevation reservoir and may be locatedon land. In some embodiments, the higher elevation reservoir may belocated at least partially above ground and the lower elevationreservoir may be located at least partially underground. In someembodiments, the higher elevation reservoir may be located entirelyabove ground and the lower elevation reservoir may be located entirelyunderground. In some embodiments, the higher elevation reservoir may belocated underground and the lower elevation reservoir may be locatedunderground. In some embodiments, the higher elevation reservoir may belocated at least partially underground and the lower elevation reservoirmay be located at least partially underground. Energy may be stored bydisplacing a high density fluid from the lower elevation reservoir tothe higher elevation reservoir by pumping a low density from the higherelevation reservoir to the lower elevation reservoir. Energy may begenerated by displacing lower density fluid from the lower elevationreservoir through a generator, generating power, and into the higherelevation reservoir by allowing higher density from the higher elevationreservoir to transfer into the lower elevation reservoir. In someembodiments, the higher elevation reservoir may comprise a tank or bodyof liquid or other reservoir located on or near the surface of theground, while the lower elevation reservoir may comprise an undergroundregion. For example, said underground region may comprise, including,but not limited to, one or more or any combination of the following: asalt cavern, or a cavern, or an excavated region, or a mine, or anunderground mine, or a cave, or an aquifer, or an oil field, or a gasfield, or subterranean storage region. Additionally, if practicallyincompressible fluids, such as liquids, are employed, the presentembodiments may enable high round trip efficiency pumped energy storagesystem which may possess multiple advantageous characteristics, whichmay include, but are not limited to, one or more or any combination ofthe following: pumps or turbines near the surface or near an accessibleregion and/or possess a high round trip efficiency due to working fluidpractical incompressibility and/or enables near full use of the volumeof an underground cavity or region. Some of the present embodiments mayenable the pump, or turbine, or electrical equipment, or other partsrequiring potential maintenance, or moving parts, or any combinationthereof to be located above ground, or at a higher elevation, or in aneasily accessible location, or any combination thereof. In someembodiments, the energy storage system may not require a pressureexchanger due to the pressure resistance of an underground space orregion. In some embodiments, the underground space or region maycomprise the lower elevation reservoir.

For example, some embodiments may comprise a higher elevation reservoirand a lower elevation reservoir, wherein the higher elevation reservoirpossesses an elevation higher than the lower elevation reservoir and maybe located on land and the lower elevation reservoir possesses anelevation lower than the higher elevation reservoir and may be locatedon land. The system may be configured to store a high density fluid anda low density fluid. Energy may be stored by displacing a high densityfluid from the lower elevation reservoir to the higher elevationreservoir by pumping a low density from the higher elevation reservoirto the lower elevation reservoir. Energy may be generated by displacingtower density fluid from the lower elevation reservoir through agenerator, generating power, and into the higher elevation reservoir byallowing higher density from the higher elevation reservoir to transferinto the lower elevation reservoir. In some embodiments, displacement ofhigh density fluid and/or low density fluid may involve directdisplacement within a tank. In some embodiments, displacement of highdensity fluid and/or low density fluid may be conducted by passing thefluids through a pressure exchanger located at or near or below theelevation of the lower elevation reservoir. The pressure exchanger maybe located along the pipes which may transfer the fluids between thehigher elevation and lower elevation reservoirs. A pressure exchangermay enable the pressure of one fluid to displace or pump or result inthe transfer of the other fluid by exchanging kinetic energy orhydraulic pressure or pressure. A pressure exchanger may enable theexchange of pressure between high pressure fluids while enabling thelower elevation reservoir to operate at a low pressure state or at apressure near atmospheric pressure. In some embodiments, the pump and/orgenerator pump may be located near the higher elevation reservoir. Insome embodiments, the energy storage system may employ reservoirscomprising rigid tanks. In some embodiments, the total volume of liquidor fluid in each reservoir may remain relatively constant regardless ofthe charge state of the energy storage system.

Note: In some embodiments, tanks, pumps, pressure exchangers, and/orother pieces of equipment may be modular, or may be mass manufactured,or may be serial manufactured, or any combination thereof.

Note: In some embodiments, more than one pressure exchanger may beemployed.

Note: In some embodiments, employing water or seawater as a low densityfluid, and/or brine or aqueous brine as a high density fluid, may enablethe use of open air reservoirs or bodies of water for the higherelevation reservoir, or lower elevation reservoir, or any combinationthereof.

Note: In some embodiments, employing water or seawater as a low densityfluid, and/or brine or aqueous brine as a high density fluid, may enablethe use of floating roof tanks, or tank or reservoir designs typicallyemployed in municipal water storage or waste water storage, or anycombination thereof for the higher elevation reservoir, or lowerelevation reservoir, or any combination thereof.

Note: In figures, the label ‘ocean’ may be employed to described anexample water body. Other water bodies, instead of or in addition to,‘ocean’, may be employed. For example, water bodies may include, but arenot limited to, one or more or any combination of the following: oceans,or seas, or lakes, or mines, or excavated ground filled with water, orunderground cavities, or aquifers, or ponds, or storage reservoirs, orany combination thereof may be employed as bodies of water.

Note: ‘Low density liquid’ or ‘LDL’ may be provided as a type of lowdensity fluid. Other fluids instead of, or in addition to, liquids, maybe employed where ‘Low density liquid’ or ‘LDL’ may be described.

Note: ‘High density liquid’ or ‘HDL’ may be provided as a type of highdensity fluid. Other fluids instead of, or in addition to, liquids, maybe employed where ‘How density liquid’ or ‘HDL’ may be described.

Note: In some embodiments, in an overpressure event or in a situationwith risk of an overpressure event, the system may release high densityfluid, or low density fluid, or any combination thereof, to, forexample, prevent damage to the system. If, for example, the high densityfluid comprises water, or a salt, or a brine, or any combinationthereof, or the low density fluid comprises water, or a salt, or abrine, or any combination thereof, I some embodiments, the fluid releasemay have negligible impact on the marine environment, or chemicalcomposition, or chemical constituents, or any combination thereof in anadjacent water body, or ocean, or sea, or lake, or any combinationthereof, if applicable. For example, if the fluid pressure near a lowerelevation reservoir increases to a pressure near a tolerance pressure ora threshold pressure, a pressure release or valve may open to releasefluid to relieve at least a portion of pressure. In some embodiments,said pressure release valve may be located near or in the lowerelevation reservoir, or near or in a pressure exchanger, or near or in apump, or near or in a generator, or near or in a pipe, or near or in avalve, or any combination thereof. In some embodiments, said pressurerelease valve may be located near or in the higher elevation reservoir,or near or in a pump, or near or in a generator, or near or in a pipe,or near or in a valve, or near or in a pressure exchanger, or anycombination thereof.

Note: In some embodiments, a buffer tank may be located near orconnected to an interconnected pipeline near a pressure exchanger. Insome embodiments, the buffer tank may comprise a floating roof tank. Forexample, in some embodiments, the pressure exchanger may be located onland, and an interconnected buffer tank may possess a floating roof andmay add or release fluid in response to sudden changes in fluidpressure. A floating roof buffer tank may be employed, for example,between a pressure exchanger and a lower elevation reservoir, at aboutthe same elevation as the pressure exchanger. It may be desirable for afloating roof buffer tank to be connectable or disconnectable and may beemployed when and where the pressure of the fluid should be at or nearequilibrium with the ambient pressure conditions.

Note: A storage tank may comprise an example storage unit, or storagevessel, or storage mechanism. A reservoir may comprise storage units, orstorage vessels, or storage mechanisms.

Note: Some embodiments may employ water as the low density fluid andliquid sulfur as the high density fluid. The density difference betweenwater and liquid sulfur is about 1 kg/L, enabling significant energydensity. Low viscosity liquid sulfur may be at a temperature of about117 degrees Celsius to about 151 degrees Celsius, at which the vaporpressure of water is about 1.8 bar to 4.91 bar. The higher elevationreservoir may need to be pressurized at about 1.8 bar to 4.91 bar toensure the water remains a liquid phase. Liquid sulfur between about 117degrees Celsius to about 151 degrees Celsius possesses a viscosity lessthan about 15 cP. Liquid sulfur is practically insoluble in water. Thepresent embodiment may require heating to maintain the temperature ofthe liquid sulfur and the water, and/or the present embodiment mayrequire or benefit from insulation of the tanks, or pumps, or pipes, orother equipment to, for example, minimize heat losses into theenvironment, or prevent the liquid sulfur from cooling below its meltingpoint, or any combination thereof. In some embodiments, heat may besupplied from, including, but not limited to, one or more or anycombination of the following: solar thermal heat, or waste heat, or heatpump, or electricity, or natural gas, or combustion, or chemicalreaction, or fertilizer production, or burning sulfur, or combustion ofsulfur, or the production of sulfuric acid, or any combination thereof.

Note: In some embodiments employing liquid sulfur or other above ambienttemperature fluids, it may be desirable to maintain the liquid sulfur ata temperature near 150 degrees Celsius to provide a buffer to preventliquid sulfur from cooling to a temperature less than or equal to itsfreezing point or melting point to, for example, prevent the potentialclogging of pipes or equipment.

Note: In some embodiments employing liquid sulfur or other above ambienttemperature fluids, it may be desirable to employ insulated and/orheated pipelines or flow lines.

Note: Electricity transmission may be conducted using, including, butnot limited to, a subsea or submarine cable, or an above ground cable,or a electricity transfer ship, or an underground cable, or a buriedcable, or hydraulic transfer, or any combination thereof.

Note: In some embodiments, the elevation of the higher elevationreservoir may be higher than or equal to the elevation of the surface ofthe body of water or body of liquid. For example, the elevation of thehigher elevation reservoir may be higher than or equal to one or more orany combination of the following relative to the elevation of thesurface of the body of water or body of liquid: 0 meters, or 5 meters,or 10 meters, or 20 meters, or 30 meters, or 40 meters, or 50 meters, or60 meters, or 70 meters, or 80 meters, or 90 meters, or 100 meters, or120 meters, or 140 meters, or 160 meters, or 15 meters, or 200 meters,or 250 meters, or 300 meters, or 350 meters, or 400 meters, or 450meters, or 500 meters, or 550 meters, or 600 meters, or 650 meters, or700 meters, or 750 meters, or 800 meters, or 850 meters, or 900 meters,or 950 meters, or 1000 meters.

Note: In some embodiments, the elevation of the higher elevationreservoir may be lower than or equal to the elevation of the surface ofthe body of water or body of liquid, which may mean the higher elevationreservoir is located beneath the body of water or body of liquid. Forexample, the elevation of the higher elevation reservoir may be lowerthan or equal to one or more or any combination of the followingrelative to the elevation of the surface of the body of water or body ofliquid: 0 meters, or −5 meters, or −10 meters, or −20 meters, or −30meters, or −40 meters, or −50 meters, or −60 meters, or −70 meters, or−80 meters, or −90 meters, or −100 meters, or −120 meters, or −140meters, or −160 meters, or −15 meters, or −200 meters, or −250 meters,or −300 meters, or −350 meters, or −400 meters, or −450 meters, or −500meters, or −550 meters, or −600 meters, or −650 meters, or −700 meters,or −750 meters, or −800 meters, or −850 meters, or −900 meters, or −950meters, or −1000 meters.

Note: In some embodiments, the higher elevation reservoir may be locatedunderwater, although may be floating or suspended underwater. In someembodiments, it may be desirable for the higher elevation reservoir tobe located underwater, or to be floating or suspended underwater, suchas to minimize or prevent exposure of the higher elevation reservoir towaves, or wind, or debris, which may be more prevalent near the surfaceof the water than underwater at a sufficient depth.

A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid which has ahigher density than the first fluid;

a pump; and

a generator;

wherein the pump, generator, and the first and second reservoir areoperatively connected such that power is stored by displacing the secondfluid which has a higher density than the first fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir and power is generated ordischarged by allowing the first fluid in the second storage reservoirto return to the first storage reservoir; and

wherein the first fluid is a liquid.

Additional Physical Divider in Reservoir or Tank Notes

Adjustable Tank Divider

It may be possible for a boundary layer or stratification layer to format the liquid-liquid interface between the high density fluid and lowdensity fluid. It may be desirable to minimize the size or volume ofsaid boundary layers or stratification layers to, for example, maximizeusable tank capacity. It may be desirable to minimize the possibletransfer or diffusion of chemical components in the high density fluidinto the low density fluid and/or vise versa.

In some embodiments, systems and methods for minimizing mixing or heattransfer between the high density fluid and low density fluid maycomprise mechanisms to minimize turbulence or mixing when fluids arebeing added or removed or otherwise transferred into or out of a tank orvessel. For example, a tank may employ diffusers which may minimizeturbulence when adding or removing or otherwise transferring fluids. Forexample, diffusers may promote the formation of laminar flow when addingor removing or otherwise transferring fluids, which may prevent mixingbetween fluids. For example, a system may employ kinetic energy or waveor motion damping mechanisms, which may convert said kinetic energy orwave or motion into heat, or liquid, or electricity, or sound, ortransfer kinetic energy, or otherwise remove or transfer away turbulenceor waves or mixing from liquid-liquid interfaces or boundary layers orstratification layers or fluid interfaces. For example, some embodimentsmay employ features or walls or dividers storing or comprising acompressible fluid, such as a gas or a foam, which may convert kineticenergy into heat.

In some embodiments, systems and methods for minimizing mixing betweenfluids may comprise physical dividers. In some embodiments, physicaldividers may comprise a solid material which may be located, at least inpart, between two fluids, or between the high density fluid and lowdensity fluid within a tank or other form of reservoir. Physicaldividers may prevent mixing between fluids by, including, but notlimited to, one or more or any combination of the following: minimizingthe surface area which fluids are in direct contact, or preventing orminimizing turbulence or waves or fluid motion from traveling betweenfluids at or near fluid interfaces inside a tank, or provide aninsulative divider which may prevent or minimize the transfer of heatbetween liquid phases within a tank.

In some embodiments, the volume of each fluid in the tank may changedepending on the state of charge of an energy storage system. If therelative volumes of each liquid phase or liquid layer in a tank change,the location or elevation of fluid interfaces or hypothetical fluidinterfaces inside the tank may also change, which may result in the needfor physical dividers to move. In some embodiments, it may be desirablefor the movement of the physical dividers to match or attempt to atleast partially match the movement of a fluid or liquid-liquid interfaceor of a hypothetical liquid-liquid interface or hypothetical fluidinterface. For example, if the elevation of a liquid-liquid interface orthe liquid level layer decreases by a first amount of centimeters, itmay be desirable for the physical divider to decrease by about the sameamount of centimeters, plus or minus a tolerance amount. Said toleranceamount may comprise the maximum amount of deviation in movement betweenthe physical divider and/or movement in the liquid-liquid interfacewhile maintaining layer separation or without substantial mixing betweenlayers, minus a contingency amount. Said tolerance amount may comprisethe maximum amount of deviation in position or location or elevationbetween the physical divider and/or movement in the liquid-liquidinterface while maintaining layer separation or without substantialmixing between layers, minus a contingency amount.

A physical divider may comprise a solid or liquid material. A physicaldivider may comprise including, but not limited to, one or more or acombination of the following: a plastic, or a composite, or a rubber, oran elastic material, or a polymer, or a metal, or a ceramic, or a solid,or a liquid, or a gas. A physical divider may comprise a rigid material,or a flexible material, or any combination thereof. For example, aphysical divider may comprise a rigid interior with a flexible skirtaround the perimeter of the physical divider, for example, where thephysical divider may be near or in contact with the tank walls. It maybe desirable to place a skirt at the perimeter of a physical divider orwhere a physical divider meets or nearly meets a tank wall because saidskirt may ensure a physical divider occupies a maximum cross sectionalsurface area while enabling the physical divider to be movable or mobileor capable of changing position. Said skirt may comprise a flexiblematerial. Said skirt may comprise a flexible material which returns toabout the same shape after the force which flexed the material is atleast partially relieved. Said skirt may comprise an elastic material.It may be desirable for a physical divider to have a shape of at least aportion of the cross sectional shape or area of a tank near at least onepoint where a hypothetical liquid-liquid interface may be located. Itmay be desirable for the physical divider to occupy at least a portionof the cross sectional area of a tank and/or occupy at least a portionof a surface a liquid phase and/or occupy a space or location which mayotherwise comprise a direct liquid-liquid interface and/or reduce thetotal surface area of a direct or potentially direct contactliquid-liquid interface or fluid-fluid interface.

It is important to note that ‘liquid-liquid interface’ may be providedas an example fluid-fluid interface, and other fluid-fluid interfacesinstead of or in addition to a ‘liquid-liquid interface’ may be employedor may exist where ‘liquid-liquid interface’ is described.

It is important to note that ‘liquids’ may be provided as an examplefluid, and other fluids instead of or in addition to ‘liquids’ may beemployed where ‘liquids’ are described.

In some embodiments, one or more or a combination of mechanisms may beemployed to ensure physical dividers are in the appropriate location, orare near or in or providing a barrier at a liquid-liquid interface orother fluid-fluid interface, or any combination thereof. In someembodiments, the placement or movement of a physical divider may beenabled or facilitated by a passive mechanism. For example, a passivemechanism may involve a mechanism which enables the physical divider tomove, such as rise or fall, with the level of layers or the level of aliquid-liquid interface or other fluid-fluid interface utilizing thechange in position of the liquid-liquid interface or the position orvolume of a liquid layer. For example, in some embodiments, a passivemechanism may not require an external power source or control devicebeyond external power sources or control devices involved with thepumping or transferring of fluids. It is important to note one or moreor any combination of passive mechanisms may be combined. It isimportant to note one or more or any combination of passive mechanismsmay be combined and/or may be combined with one or more or anycombination of active mechanisms.

For example a passive mechanism may comprise, including, but not limitedto, one or more or any combination of the following:

A physical divider with a density less than the density of one layer andgreater than the density of another layer, which may enable the physicaldivider to naturally gravitate to a position between the lower densitylayer and the higher density layer due to intrinsic buoyancy propertiesand/or may enable the physical divider to be positioned at theliquid-liquid or other fluid-fluid interface between two layers.

A physical divider which may utilize hydrophobicity and/orhydrophilicity and/or surface tension to facilitate its position withina tank and/or to minimize mixing between layers. For example, a physicaldivider may be located between two liquid phases wherein both liquidphases are hydrophilic and, by employing hydrophobic surfaces on atleast one side of the physical divider and/or hydrophilic surfaces on atleast one side of the physical divider, the physical divider maygravitate to a position between the two liquid phases or a position atthe liquid-liquid interface between two liquid phases. For example, aphysical divider may be located between two liquid phases wherein bothliquid phases are hydrophobic and, by employing hydrophobic surfaces onat least one side of the physical divider and/or hydrophilic surfaces onat least one side of the physical divider, the physical divider maygravitate to a position between the two liquid phases or a position atthe liquid-liquid interface between two liquid phases. For example, aphysical divider may be located between two liquid phases wherein atleast one liquid phase is hydrophilic in a temperature range and atleast one liquid phase is hydrophilic in a different temperature range,and, by employing hydrophobic surfaces on at least one side of thephysical divider and/or hydrophilic surfaces on at least one side of thephysical divider, the physical divider may gravitate to a positionbetween the two liquid phases or a position at the liquid-liquidinterface between two liquid phases. For example, a physical divider maybe located between two liquid phases and the physical divider may behydrophilic. For example, a physical divider may be located between twoliquid phases and the physical divider may be hydrophobic.

A physical divider which may utilize surface tension. For example, aphysical divider may utilize the surface tension at a liquid-liquidinterface or other fluid-fluid interface to enable positioning at aliquid-liquid interface or other fluid-fluid interface. For example, aphysical divider may utilize the difference in surface tension betweentwo liquid phases. For example, a physical divider may employ materialsurface properties, such as surface geometry, to utilize surface tensionto position a physical divider at a liquid-liquid interface. Forexample, surface tension or capillary forces may be employed to enablepositioning of the physical divider. For example, the surface tension orcapillary forces utilized may not be limited to surface tension orcapillary forces at a liquid-liquid interface, and may also include, butis not limited to, surface tension or capillary forces between thephysical divider and the tank wall, or the physical divider and tankwall in the presence of a liquid-liquid interface, or any combinationthereof.

A physical divider may employ geometry and/or initial placement orpositioning to maintain position or maintain a position at aliquid-liquid interface or at a hypothetical liquid-liquid interface.For example, a physical divider may employ a convex or concave geometricwhich may prevent the physical barrier from rising into an upper liquidlayer or falling into a lower liquid layer. For example surface tensionor suction forces or the inability for another liquid phase or fluid toenter the concave region may facilitate placement of a cup at aliquid-liquid interface. For example, in some embodiments, a physicaldivider may employ at least one concave surface and at least one convexsurface. For example, in some embodiments, a physical divider may employconvex surfaces or external siding. For example, in some embodiments, aphysical divider may employ concave surfaces or external siding. Forexample, in some embodiments, a physical divider may employ an internalcompartment with storing at least one liquid phase and/or with anopening to a layer comprising at least a portion of said stored liquidphase.

For example, a practical demonstration of an example of phenomena at afluid interface involving physical divider geometry may involvesubmerging a cup in water, filling the cup with water, then lifting thebottom of the cup above the surface of the water with the cup in aninverted or upside-down position. If the opening of the cup remainsbeneath the air—water interface or the water's surface, the water willremain in the cup. In such a scenario, even if the density of the cup isless than the density of the water, the cup may not fully float abovethe surface of the water or may not substantially rise above the surfaceof the water if the cup remains in an inverted or upside-down positionbecause of the water occupying the cup and the associated density of thewater relative to the air.

A physical divider may employ a difference in viscosity between twoliquid phases or liquid layers at a liquid-liquid interface orhypothetical liquid-liquid interface or other fluids or other fluidinterfaces. One liquid phase may possess a substantially differentviscosity than another liquid phase, and said substantially differentviscosity may be employed to help facilitate the placement of ormaintain the position of a physical divider and/or to maintain aseparation between two liquid phases.

A physical divider may employ electrostatic properties to maintain aposition and/or maintain/or enable a separation of liquid phases. Forexample, two liquid phases or layers may possess different electrostaticproperties or electrostatic charge, which may be utilized to ensureliquid-liquid separation in a tank with a physical barrier. For example,two liquid phases or layers may possess similar electrostatic propertiesor electrostatic charge, which may be utilized to ensure liquid-liquidseparation in a tank with a physical divider. For example, a physicaldivider may be designed with electrostatic properties which may preventthe physical divider from undesirably floating or sinking and/or mayenable the physical divider to maintain proper placement and/or maintaina position at a liquid-liquid interface and/or prevent or minimizemixing between liquid phases.

A physical divider may employ magnetic properties to maintain a positionand/or maintain/or enable a separation of liquid phases. For example,two liquid phases or layers may possess different magnetic properties,which may be utilized to ensure liquid-liquid separation in a tank witha physical divider. For example, two liquid phases or layers may possesssimilar magnetic properties, which may be utilized to ensureliquid-liquid separation in a tank with a physical divider. For example,a physical divider may be designed with magnetic properties which mayprevent the physical divider from undesirably floating or sinking and/ormay enable the physical divider to maintain proper placement and/ormaintain a position at a liquid-liquid interface and/or prevent orminimize mixing between liquid phases.

In some embodiments, the percentage of surface area or cross sectionalarea or both of a liquid-liquid interface or fluid-fluid interfacecovered or occupied by a physical divider may be greater than, or equalto, or less than, one or more or any combination of the following: 1%,or 5%, or 10%, or 15%, or 20%, or 25%, or 30%, or 35%, or 40%, or 45%,or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%,or 95%, or 99%, or 99.5%.

For example an active mechanism may comprise, including, but is notlimited to, one or more or any combination of the following:

In some embodiments, the physical divider's position, or shape, or anycombination thereof may be adjusted using a mechanical device or amechanical mechanism.

Density

In some embodiments, a physical divider may possess a density greaterthan the density of one or more or all the liquid phases in a thermalstorage tank.

In some embodiments, a length adjustment mechanism may be located, forexample, at or near the top of the tank.

In some embodiments, a physical divider may possess a density less thanthe density of one or more or all the liquid phases in a thermal storagetank.

In some embodiments, a length adjustment mechanism may be located, forexample, at or near the bottom of the tank.

In some embodiments a system may possess at least one physical dividerwith a density greater than the density of one or more or all the liquidphases.

Controlling Position of a Physical Divider

In some embodiments, a system may employ information on systemoperations to determine the appropriate or desired position of thephysical divider and instruct the adjustment mechanism to move thephysical divider to said appropriate or desired position. Aliquid-liquid interface or hypothetical liquid-liquid interface may moveat one, or more, or any combination of rates of change based on,including, but not limited to, one or more or a combination of thefollowing: the flow rate, or material or chemical or physicalproperties, or geometry, or the geometry of the physical divider, or thegeometry of the tank or vessel, or any combination thereof. In someembodiments, the desired position of a physical divider may change inconnection with or correlation with the change in position of aliquid-liquid interface. A system may determine or compute therelationship between the liquid flow rate of one or more liquid phasesand the rate of change in position of a liquid-liquid interface or ahypothetical liquid-liquid interface and/or employ information on saidrelationship to determine the desired position of a physical divider. Insome embodiments, said relationship may be an established equation oralgorithm. In some embodiments, said relationship, or live or semi-liveinformation on system operations, or other information, or anycombination thereof may be employed to determine the desired location ofthe physical divider at any desired time interval and/or a predictedrate of change of the desired location of the physical divider. In someembodiments, the adjustment mechanism may be controlled or instructed toadjust the position of a physical divider at a specific rate of changeor direction based on said information. Information may include, but isnot limited to, for example, information on the flow rate of one or moreliquid phases entering or exiting a thermal storage system and/orinformation on the geometry of the thermal storage tank. Information maybe computational or digital. In some embodiments, information may begathered from one or more equipment or sensors, or information may bestored in a digital or physical storage mechanism, or any combinationthereof. In some embodiments control or actions made by a system may beat least partially automated or fully automated.

Cable or Thread Based Adjustment Mechanism:

In some embodiments, the location or elevation or position of thephysical divider in a tank may be controlled or maintained or adjustedusing threads or cables attached to the physical divider, or indirectlyconnected to the physical divider, or connected to the physical dividerusing a magnetic coupling, or indirectly connected to the physicaldivider using a magnetic force, or any combination thereof. Said threadsor cables may comprise, including, but not limited to, one or more or acombination of the following: synthetic material, or organic material,or natural fiber, or composite material, or metallic material, orceramic material, or carbon material, or hydrocarbon material, orplastic, or metal, or fibrous material, or nylon, or polyvinylidenefluoride, or polyethylene, or polyester, or Dacron, or UHMWPE, or PTFE,or fluorocarbon, or carbon fibre, or cotton, or Dyneema, or Kevlar. Saidthreads or cables may be connected to an adjustment mechanism or alength adjustment mechanism. Said threads or cables may be connected toan adjustment mechanism or a length adjustment mechanism. Saidadjustment mechanism may comprise, for example, including, but notlimited to, one or more or a combination of the following: a pulley, orreel, or actuator. Said adjustment mechanism may adjust the position ofa liquid-liquid separator by adjusting the length of one or more cablesor lines.

Some embodiments may employ one cable. Some embodiments may employ onecable with a cable split near a physical divider, which may split orbranch one cable into multiple cables, wherein each of said multiplescables or branch cables may anchor or be connected to the physicaldivider, or may anchor to distributed points or locations on thephysical divider, or any combination thereof. Some embodiments mayemploy multiple cables. Some embodiments may employ one cable and oneadjustment mechanism. Some embodiments may employ multiple adjustmentmechanisms and one cable. Some embodiments may employ one adjustmentmechanism and multiple cables. Some embodiments may employ multipleadjustment mechanisms and multiple cables.

In some embodiments, such as, for example, in embodiments with at leastone physical divider positioned at an elevation below another physicaldivider and/or where a cable length adjustment mechanism is located nearthe top of the tank, it may be desirable for the threads or cablesconnected to the lower elevation physical divider to pass through thehigher elevation physical divider, which may require holes in the higherelevation physical divider which allow said threads or cables of thelower elevation physical divider to pass through the higher elevationphysical divider, while allowing the higher elevation physical dividerto operate. In some embodiments, such as, for example, in embodimentswith at least one physical divider positioned at an elevation aboveanother physical divider and/or where a cable length adjustmentmechanism is located near the bottom of the tank, it may be desirablefor the threads or cables connected to the higher elevation physicaldivider to pass through the lower elevation physical divider, which mayrequire holes in the higher elevation physical divider which allow saidthreads or cables of the lower elevation physical divider to passthrough the higher elevation physical divider, while allowing the higherelevation physical divider to operate. It may be desirable for saidthreads or cables to be as small in diameter as possible and said holesin the higher elevation physical divider to be as small in diameter aspossible to minimize mixing between liquid phases and/or minimizesurface area of direct contact liquid-liquid interface. It may bedesirable to employ surface geometry, or specific geometry of the cableor thread or hole, or any combination thereof to, for example to, forexample, minimize potential mixing between different liquid phases atsaid holes and/or at said threads or lines. It may be desirable toemploy hydrophilic, or hydrophobic, or other material property coatingor material at or in said holes and/or on said threads or cables to, forexample, minimize potential mixing between different liquid phases atsaid holes and/or at said threads or lines.

In some embodiments, it may be desirable to maximize the volume of atank occupied by a thermal storage medium and minimize the volume of atank occupied by a physical divider or both.

In some embodiments, a physical divider may be connected to at least aportion of an adjustment mechanism by a magnetic coupling, or magneticforce, or magnetic interaction, or magnetic mechanism. For example, atleast a portion of the siding or perimeter of a physical divider may bemagnetic or may comprise a magnet and/or an actuator outside of the tankmay comprise a magnet and/or said actuator may control the position of aphysical divider due to the magnetic force connecting the actuator tothe physical divider. In some embodiments, employing a magneticmechanism may prevent or reduce mixing of layers because, for example, amagnetic mechanism may enable control or movement of the physicaldivider with less moving parts or holes in the tank or physical divider.In some embodiments, the use of a magnetic mechanism may reduce the tankvolume occupied by the adjustment mechanism and/or tank divider, whichmay increase the available volume or percentage of volume available foror occupied by a thermal storage medium.

In some embodiments, the position of a physical divider may be adjustedby one or more or any combination of a physical bolt or screw or athreaded rod. A rotation mechanism, such as an electric motor, may beconnected to said physical bolt or screw or a threaded rod. The physicalbolt or screw or a threaded rod may be connected to a physical divider.In some embodiments, the physical bolt or screw or a threaded rod may beattached to the top of a physical divider. In some embodiments, aphysical divider may possess complementary threads to the threads of thephysical bolt or screw or a threaded rod and the physical bolt or screwor a threaded rod may pass through the physical divider. Depending onthe direction of rotation, the position or elevation of a physicaldivider may change based on the rotation of the physical bolt or screwor a threaded rod in the presence of complementary threads in thephysical divider. In some embodiments, a single physical bolt or screwor a threaded rod may be employed. In some embodiments, a physical boltor screw or a threaded rod may be employed, however multiplenon-threaded or threaded guide posts or rods, which may ensure aphysical divider remains aligned or in a proper position, may also beemployed. In some embodiments, multiple physical bolts or screws orthreaded rods may be employed. In some embodiments with more than onephysical divider, it may be desirable to employ different physical boltsor screws or threaded rods to adjust the position of each physicaldivider. In some embodiments with more than one physical divider, it maybe desirable to employ the same physical bolts or screws or threadedrods to adjust the position of each physical divider.

In some embodiments, an adjustment mechanism may help maintain theposition of a physical divider, for example, by preventing the physicaldivider from becoming misaligned or crooked.

In some embodiments, physical dividers may possess an electrostaticchange. In some embodiments, physical dividers an electrostatic chargemay be provided to a physical divider and/or electricity or an electriccharge from an energy source may be provided to a physical divider. Insome embodiments, an electrostatic charge or electrical charge may beemployed to facilitate the position of a physical divider at aliquid-liquid interface or hypothetical liquid-liquid interface. In someembodiments, an electrostatic charge or electrical charge may beemployed to further minimize mixing between liquid layers near aphysical divider.

In some embodiments, the higher elevation reservoir may be integratedwith a power transformer, or crew quarters, or any combination thereof.For example, in some embodiments, the higher elevation reservoir maycomprise a floating power transformer or may incorporate or be adjacentto a floating power transformer.

Active mechanism may involve physical movement requiring power input tooperate and/or may involve using mechanical device, for example, whichmay include, but is not limited to, a cable, or actuator, or rotatingbolt or screw, or magnetism, or magnetic bearing, or magnetic actuator,or powered electrostatic charge, or electrical charge.

Note: ‘To attempt to at least partially match’ may mean ensuring theposition of a physical divider is within the tolerance amount of aliquid-liquid interface or hypothetical liquid-liquid interface.

Note: ‘A hypothetical liquid-liquid interface’ may mean the likelylocation of a liquid-liquid interface or other fluid-fluid interface,even if liquid layers or fluid layers or fluids are not or are minimallyin direct contact within a tank. A hypothetical liquid-liquid interfacemay be determined, for example, based on, including, but not limited to,one or more or a combination thereof: the volume of a liquid layer orthe volume of each liquid layer in the tank and the geometry of thetank, or by sensors employing light, or viscosity, or density, or color,or other means to determine the location of a layer and the transitionfrom one layer to another layer, or any combination thereof.

[Diffuser to minimize mixing or turbulence between the layers and/ormaintain a liquid-liquid interface] [physical barrier or divider placedbetween at least a portion of the layers which may minimize or preventmixing between the layers]

Storage of Liquid Phases

Densities

Density differences may be primarily driven by concentration of one ormore chemical components, because each liquid phase may possessdifference concentration or composition than the other liquid phases]

Layering in tank may occur with liquid-liquid interfaces and minimalmixing or turbulence in tank, which may be facilitated with diffusers.

Due to defined liquid-liquid interface and/or defined densitydifferences physical dividers may be placed or located between thelayers near or at liquid-liquid interfaces.

Dividers may be employed to, for example:

Minimize Mixing Between Liquid Phases

Minimize Heat Transfer Between Liquid Phases

Enable more turbulent flow or less complicated or expensive diffusers orinlets or outlets by, for example, preventing or minimizing mixingbetween layers.

Enable Greater Energy Densities

Minimize or Reduce Potential Unusable Tank Volume at Liquid-LiquidInterfaces

Dividers may be located in liquid-liquid interfaces due to customizeddensities which may be greater than the density of a layer above thedivider and less than the density of the layer below the divider.Buoyancy based placement of dividers may comprise passive placement ofdividers.

Dividers may be located in liquid-liquid interfaces due to mechanical orother active mechanisms. Said active mechanism placement may involvemoving the location or elevation or placement of the divider by meansindependent of the buoyancy of the divider in the layers or liquidphases. Said active mechanism placement may involve moving the locationor elevation or placement of the divider in response to changes in theenergy storage system, such as, including, but not limited to, fluidsentering or exiting the storage tank, or changes in the volume of one ormore fluids in the storage tank, or any combination thereof.

Some embodiments may involve both active and/or passive physicalplacement or movement of dividers.

Example Application Notes

Background

In 2015, Hawaii was the first US state to sign into law a 100% renewableenergy mandate, requiring the state to generate 100% of its power fromrenewable energy by 2045. Hawaii has an isolated electricity grid andlimited hydropower resources, making Hawaii's transition to 100%renewable energy challenging compared to other US states.

Fortunately, Hawaii has favorable attributes for renewable energyprojects. Hawaii electricity prices for large industrial power userswere $0.2172 per kWh on Oahu and $0.2915 per kWh on Big Island,significantly greater than the levelized cost of electricity from mostsolar and wind projects and about 184% and 281% greater, respectively,than the average price of $0.0765 per kWh for industrial power users onthe US mainland. Hawaii Electric Power Corporation, Hawaii's electricpower utility, is an investment grade credit rated electric poweroff-taker. Hawaii has relatively significant power capacity, with1,794.5 MW of firm capacity and 853 MW of non-firm capacity on theisland of Oahu, and 213.3 MW of firm capacity and 155.4 MW of non-firmcapacity on the Big Island. Hawaii has an abundance of consistent solarand wind resources and relatively consistent climate.

Hawaii's plans for transitioning to 100% renewable energy rely onintermittent power sources, solar and wind, combined with energystorage. Currently, any new solar project developed in Hawaii must beco-developed with energy storage. To date, Hawaii energy storagecomprises almost entirely lithium ion battery projects. Mostsignificantly, on the Island of Oahu, Hi. plans to replace the 15 MW AEScoal power plant with a 185 MW. 565 MWh lithium ion battery project bySeptember 2022. Lithium ion batteries, however, are unlikely to providethe long term energy storage Hawaii needs to reliably and sustainablytransition to 100% renewable energy. Lithium-ion batteries have limitedcycle lives and generally need to be replaced after 10 years.Lithium-ion batteries are currently non-recyclable and are made ofscarce materials, including lithium, graphite, and cobalt. Additionally,Hawaii will require increasingly longer duration energy storage toensure power grid reliability while increasing the penetration ofintermittent solar and wind power, and lithium ion batteries areill-suited for long duration energy storage because lithium ionbatteries are unable to decouple power capacity from energy capacity.Hawaii will need sustainable and reliable long duration electricitystorage to achieve its 100% renewable energy mandate.

Technical Overview of FLUID DISPLACEMENT ENERGY STORAGE

FLUID DISPLACEMENT ENERGY STORAGE is a long duration energy storagetechnology which stores power in the gravitational potential energy ofdisplacing a high density liquid with a low density liquid between tworegions of different elevation. In some embodiments, FLUID DISPLACEMENTENERGY STORAGE has a lower elevation reservoir located beneath thesurface of a body of water, and a higher elevation reservoir locatednear or above the surface of a body of water or otherwise at anelevation greater than the elevation of the lower elevation reservoir.Some versions of FLUID DISPLACEMENT ENERGY STORAGE employ a floatinghigher elevation reservoir, which may comprise a floating storagevessel, such as an FSO. Some versions of FLUID DISPLACEMENT ENERGYSTORAGE employ a higher elevation reservoir located on land and a lowerelevation reservoir located under the water. FLUID DISPLACEMENT ENERGYSTORAGE may comprise a closed system, meaning all working fluids areinternally contained within the system and are not in contact with thesurrounding ocean water. Some embodiments may be built using equipmentand materials well-established in other applications, such as inpipelines, offshore oil & gas projects, hydroelectric dams, municipalwater systems, and desalination facilities.

The energy stored in FLUID DISPLACEMENT ENERGY STORAGE may be primarilydependent on the difference in elevation between the higher elevationreservoir and lower elevation reservoir, the difference in densitybetween the high density liquid (HDL) and low density liquid (LDL), andthe volume of high density liquid and low density liquid. Generally, thegreater the density difference between the HDL and the LDL, and/or thegreater the elevation difference between the lower elevation reservoirand higher elevation reservoir, the greater the energy density of thesystem. In addition to energy density, factors for selecting HDL-LDLpairs include compatibility, availability, cost, and environmentalimpact. Example HDL-LDL pairs selected based on the aforementionedcriteria include, but are not limited to, those shown in Table 1. Table2 shows the energy density of each HDL-LDL pair at elevation differencesof 1,000 meters, 1,500 meters, 2,000 meters, 2,500 meters, 3,000 meters,3,500 meters, and 4,000 meters. Tables 3-5 show example pros and cons ofeach HDL-LDL pair provided in Table 1.

TABLE 1 Selected Example High Density Liquid - Low Density Liquid PairsHigh Low Density Density Density Density Density Difference Label Liquid(kg/L) Liquid (kg/L) (kg/L) Pair #1 Brine 1.30 Freshwater 1.00 0.30(e.g. Magnesium Chloride and/or Calcium Chloride + Water) Pair #2Seawater 1.03 n-Butane 0.57 0.46 Pair #3 Brine 1.30 n-Butane 0.57 0.73(e.g. Magnesium Chloride and/or Calcium Chloride + Water)

TABLE 2 Calculated Energy Density (kWh per m³) of Selected Example HDL -LDL Pairs vs. Elevation Difference 1,000 m 1,500 m 2,000 m 2,500 m 3,000m 3,500 m 4,000 m Pair 0.82 1.23 1.64 2.04 2.45 2.86 3.27 #1 Pair 1.251.88 2.51 3.13 3.76 4.38 5.01 #2 Pair 1.99 2.99 3.98 4.97 5.97 6.96 7.96#3

TABLE 3 Example Brine (HDL) - Freshwater (LDL) Pair Pros and Cons ProsCons Low cost HDL and LDL 0.3 kg/L density difference is lower AbundantHDL and LDL than pairs with n-Butane LDL Same composition as oceanwater, Subsea pressure exchanger may be minimal environmental impact inevent required because the HDL has density of leak greater than oceanwater Both LDL and HDL Non-flammable LDL cannot be used as a fuel ifneeded Relatively low cost storage structures Non-toxic Standardhydroelectric turbine may be employed as pump/generator

TABLE 4 Example Seawater (HDL) - n-Butane (LDL) Pair Pros and Cons ProsCons 0.46 kg/L density difference n-Butane cost $0.50-2.00 gallonNon-toxic depending on commodity prices n-Butane does not form‘gas-hydrates’ Surface tank must be regulated at about In the event of aleak, n-Butane cannot 40 degrees F. to ensure n-Butaue form a ‘slick’because it is a ‘gas- remains a liquid without liquid’ and n-Butane isnot a potent pressurization, which is fortunately greenhouse gas aboutthe same temperature as deep-sea Subsea tank at pressure equilibriumocean water (Alternatively surface tank with surrounding ocean waterwithout may be pressurized at 2-3 Bar) a pressure exchanger, even inclosed n-Butane is flammable system, due to Seawater HDL having the samedensity as the surrounding ocean water Hydraulic power recovery turbine(HPRT) may be employed as electric hydraulic pump/generator LDL can beused as a fuel if needed

TABLE 5 Example Brine (HDL) - n-Butane (LDL) Pair Pros and Cons ProsCons 0.73 kg/L density difference n-Butane cost $0.50-2.00 gallonNou-toxic depending on commodity prices n-Butane does not form‘gas-hydrates’ Surface tank must be regulated at about In the event of aleak, n-Butane cannot 40 degrees F. to ensure n-Butane form a ‘slick’because it is a ‘gas- remains a liquid without liquid’ and n-Butane isnot a potent pressurization, which is fortunately greenhouse gas aboutthe same temperature as deep-sea Hydraulic power recovery turbine oceanwater (Alternatively surface tank (HPRT) may be employed as electric maybe pressurized at 2-3 Bar) hydraulic pump/generator Subsea pressureexchanger may be LDL can be used as a fuel if needed required becausethe HDL has density greater than ocean water n-Butane is flammable

Hawaiian Islands' Geography and FLUID DISPLACEMENT ENERGY STORAGE

Hawaii is a geographically favorable location for FLUID DISPLACEMENTENERGY STORAGE long duration energy storage. The largest power plant andrelated power transmission infrastructure on the Hawaii Island of Oahuare within 7.1 kilometers of 1,000 meter ocean water depth and 15.2kilometers of 2,000 meter ocean water depth. The largest power plant andrelated power transmission infrastructure on Hawaii's Big Island arewithin 2.5 kilometers of 1,000 meter ocean water depth, 3.9 kilometersof 1,500 meter ocean water depth, 5.8 kilometers of 2,000 meter oceanwater depth, 13.7 kilometers of 3,000 meter ocean water depth, and 17.3kilometers of 4,000 meter ocean water depth. FLUID DISPLACEMENT ENERGYSTORAGE may be uniquely suited to provide the sustainable and reliablelong duration electricity storage Hawaii requires to achieve its 100%renewable energy mandate.

Example FLUID DISPLACEMENT ENERGY STORAGE Demonstration Project

Natural Energy Laboratory of Hawaii Authority (NELHA) Hawaii OceanScience and Technology (HOST) Park (‘NELHA HOST Park’) in Kailua-Kona,Hi. may be selected as a potential FLUID DISPLACEMENT ENERGY STORAGEproject location.

FLUID DISPLACEMENT ENERGY STORAGE Potential Demonstration ProjectOverview

Summary: The design, working fluids, and water depths may be chosen tominimize construction timeline and reduce supply chain risk, includingby enabling the use of a wide range of equipment vendors. The projectmay be co-developed with a solar PV plant to demonstrate FLUIDDISPLACEMENT ENERGY STORAGE's synergy with intermittent renewable energysources and enable an offtake agreement.

Example Project Specs:

Power Capacity: 3 MW

Energy Capacity: 30 MWh

Lower Elevation Reservoir Water Depth: 1,500 meters

Pipeline Distance (shore to lower elevation reservoir): 3,900 meters

HDL: Brine

LDL: Water

Diagrams of Onshore-Offshore FLUID DISPLACEMENT ENERGY STORAGE Version

Please Note: All diagrams are simplified representations. Pipelines arelikely not suspended above the sea floor. Relative sizes and distancesare not intended to be representative of actual relative sizes anddistances in a real system.

Example Description of Components and Example Vendors

Label in Figure Description 1 Higher elevation reservoir. Onshore HDLand LDL storage tank. May comprise a stratified layer water tank,similar to tanks employed in chilled water thermal storage. Stratifiedlayering may be maintained or facilitated by diffusers, or by a floatingbarrier, or both. 2 Hydroelectric turbine. In the present version, ‘2’may only interact with the low density liquid, which, may comprisefreshwater. The hydroelectric turbine employed in ‘2’ may be the same asor similar to hydroelectric turbines employed in pumped-hydro. 3 Subseapipeline between higher elevation reservoir and pressure exchanger nearlower elevation reservoir. Designed to transfer LDL. Subsea pipelinesmay be manufactured by a wide range of vendors. Subsea large diametersubsea pipelines may generally be installed by pipeline installationvessels. 4 Subsea pipeline between pressure exchanger and lowerelevation reservoir. May be designed to transfer LDL. 5 Lower elevationreservoir. May comprise a subsea HDL and LDL storage tank. 6 Subseapipeline between lower elevation reservoir and pressure exchanger. Maybe designed to transfer HDL. 7 Subsea pipeline between pressureexchanger and higher elevation reservoir. May be designed to transferHDL. PX Pressure exchange. Pressure exchanger or other power or energytransfer or recovery device may be located subsea near the lowerelevation reservoir. Pressure exchangers may be well established In thereverse osmosis desalination industry and may be known to have powerrecovery or power transfer efficiencies up to 98%.

Example Figures of Stratified Tank

Note: Darker color or darker shaded fluid may comprise high densityliquid.

Note: Lighter color or lighter shaded fluid may comprise low densityliquid and/or may comprise a water, brackish water, or freshwater.

In some embodiments, brine may be periodically or continuouslyconcentrated or water may be periodically or continuously removed frombrine. For example, the brine may be concentrated using distillation orevaporation.

In some embodiments, low density liquid or freshwater may be purified orsalt may be removed periodically or continuously. For example, the lowdensity liquid or freshwater may be purified by means of reverse osmosisor membrane based process or by a desalination process orelectrodialysis.

Desalination Embodiments

1. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump;

wherein the pump and the first and the second reservoir are operativelyconnected such that power is stored by displacing the second fluid inthe second storage reservoir by pumping the first fluid from the firststorage reservoir to the second storage reservoir and such that power isgenerated by allowing the pumped first fluid in the second storagereservoir to exit the second reservoir; and wherein the first fluid is aliquid.

2. The system of embodiment 1 wherein the system is configured togenerate power by transferring the first fluid into a power recoverydevice.

3. The system of embodiment 2 wherein said power recovery devicecomprises a pressure exchanger.

4. The system of embodiment 2 wherein said power recovery device isconfigured to transfer the power from the first fluid to a desalinationfeed stream.

5. The system of embodiment 2 wherein said power recovery device isconfigured to extract power from the first fluid to pressurize adesalination feed comprising water.

6. The system of embodiment 5 wherein said desalination feed comprisingwater comprises seawater or treated seawater.

7. The system of embodiment 5 wherein the system is configured such thatsaid pressurized desalination feed comprising water is transferred intoa reverse osmosis desalination system.

8. The system of embodiment 2 wherein the system is configured such thatthe first fluid is transferred into the first storage reservoir aftersaid power recovery.

9. The system of embodiment 1 wherein the first fluid comprises ahydrocarbon, butane, propane, LPG, water, ammonia, ethanol, methanol,kerosene, or any mixture thereof.

10. The system of embodiment 1 wherein the system is configured suchthat power in the first fluid is employed to generate electricity forpressurizing a desalination feed water.

11. The system of embodiment 10 wherein the system is configured suchthat the proportion of power converted into electricity relative to theproportion of power transferred to pressurize the desalination feedwater is adjustable.

12. The system of embodiment 5 wherein the system is configured suchthat the first fluid transferred into a power recovery device comprisesa pressure greater than an osmotic pressure of the desalination feedcomprising water.

13. The system of embodiment 1 wherein the first fluid comprises adesalination feed comprising water.

14. The system of embodiment 13 wherein the system is configured suchthat power is generated by transferring the low density fluid into adesalination system.

15. The system of embodiment 14 wherein the system is configured suchthat the first fluid transferred to a desalination system comprises apressure greater than the osmotic pressure of the desalination feedcomprising water.

16. The system of embodiment 13 wherein the system is configured suchthat at least a portion of the power in the first fluid is recoveredusing a power recovery device before transferring the first fluid to adesalination system.

17. The system of embodiment 13 wherein the system is configured suchthat at least a first portion of the first fluid is transferred to anelectric generator and at least a second portion of the first fluid istransferred to a desalination system,

wherein the electric generator generates electricity from at least aportion of the generated power in the first fluid, and

wherein the desalination system converts at least a portion of thegenerated power in the first fluid into desalinated water.

18. The system of embodiment 17 wherein the system is configured suchthat the proportion of first fluid transferred to the desalinationsystem and the proportion of first fluid transferred to the electricgenerator is adjustable.

19. The system of embodiment 17 wherein the system is configured suchthat the proportion of power in the first fluid transferred to thedesalination system and the proportion of power in the first fluidtransferred to the electric generator is adjustable.

20. The system of embodiment 13 wherein the system is configured suchthat the first fluid exiting the second storage reservoir is transferredinto a desalination system to produce desalinated water.

21. The system of embodiment 20 wherein desalination feed comprisingwater is added to the first storage reservoir to make up for theproduced desalinated water.

22. The system of embodiment 13 the system is configured such that thefirst fluid exiting the second storage reservoir is transferred into adesalination system to separate the first fluid into a desalinated waterpermeate and a desalination retentate using a semipermeable membrane.

23. The system of embodiment 1 wherein the low density fluid comprisesdesalinated water.

24. The system of embodiment 1 wherein the system is configured suchthat the stored power is employed to desalinate water.

25. The system of embodiment 24 wherein the system is configured suchthat the desalinated water is converted into chemicals selected from thegroup consisting of hydrogen, oxygen, synthetic fuels, fuels, ammonia,hydrogen derived chemicals, carbon dioxide derived chemicals, airderived chemicals, and any mixture thereof.

26. The system of embodiment 1 wherein the system is configured suchthat the higher elevation reservoir is locatable on land, floating onwater, or underwater.

27. The system of embodiment 24 wherein the system is configured suchthat the desalinated water is transportable by a pipeline, a riser, aship, an aircraft, a train, a truck, or a conveyor belt.

28. The system of embodiment 1 wherein the pump is configured topressurize a desalination feed comprising water.

29. A process for storing power and desalinating water comprising:

storing a first fluid in a first storage reservoir:

storing a second fluid which has a higher density than the first fluidin a second storage reservoir located at a lower elevation than thefirst storage reservoir;

operatively connecting a pump and the first and second reservoir suchthat power is stored by displacing the second fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir; and

allowing the first fluid to exit the second storage reservoir andpressure exchange with a desalination feed comprising water to generatepower.

30. A process for storing power and desalinating water comprising:

storing a first fluid in a first storage reservoir;

storing a second fluid which has a higher density than the first fluidin a second storage reservoir located at a lower elevation than thefirst storage reservoir,

operatively connecting a pump and the first and second reservoir suchthat power is stored by displacing the second fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir; and

allowing the first fluid to exit the second storage reservoir and entera desalination system;

wherein the first fluid comprises a desalination feed comprising water.

Brine-Water Embodiments

1. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump; and

a generator;

wherein the pump, the generator, and the first and the second reservoirare operatively connected such that power is stored by displacing thesecond fluid in the second storage reservoir by pumping the first fluidin the first storage reservoir to the second storage reservoir and poweris generated or discharged by allowing the first fluid in the secondstorage reservoir to return to the first storage reservoir; and

wherein the first fluid is a liquid.

2. The system of embodiment 1 wherein the high density fluid is solublein the low density fluid.

3. The system of embodiment 1 wherein the second storage reservoircomprises at least one storage unit within it and wherein the system isconfigured such that the low density fluid and the high density fluidare storable within the same storage unit in the second storagereservoir.

4. The system of embodiment 3 wherein the system is configured such thatthe low density fluid is located above the high density fluid within thestorage unit.

5. The system of embodiment 3 wherein the system is configured such thata fluid-fluid interface separates the low density fluid from the highdensity fluid in the storage unit.

6. The system of embodiment 3 wherein the system is configured such thata chemocline or chemocline layer separates the low density fluid fromthe high density fluid.

7. The system of embodiment 3 wherein the system is configured such thata physical divider separates the low density fluid from the high densityfluid.

8. The system of embodiment 7 wherein the system is configured such thatthe physical divider occupies at least 50% of the cross sectional areaotherwise occupied by a fluid-fluid interface in the absence of thephysical divider.

9. The system of embodiment 7 wherein the system is configured such thatan elevation of the physical divider adjusts to follow a change inelevation of the fluid-fluid interface that would be present in theabsence of the physical divider.

10. The system of embodiment 7 wherein the system is configured suchthat the physical divider is floating.

11. The system of embodiment 7 wherein the system is configured suchthat the density of the physical divider is greater than the density ofthe low density fluid and less than the density of the high densityfluid.

12. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises at least one first reservoirstorage unit within it and the second storage reservoir comprises atleast one second reservoir storage unit within it and wherein the systemis configured such that the high density fluid and low density fluid arestored in the same storage units within the first storage reservoir andthe second storage reservoir.

13. The system of embodiment 2 wherein the system is configured suchthat at least a portion of high density fluid mixes with at least aportion of low density fluid.

14. The system of embodiment 13 wherein the system is configured suchthat at least a portion of high density fluid is removed from the lowdensity fluid by separation.

15. The system of embodiment 14 wherein the system is configured suchthat said separation comprises reverse osmosis, or forward osmosis, ordistillation, or evaporation, or electrodialysis, or gravitationalseparation, or decanting, or coalescing, or centrifuge, or filtration,or cryodesalination, or freeze desalination, solventing out, orprecipitation, or extraction, or extractive distillation.

16. The system of embodiment 2 wherein the system is configured suchthat at least a portion of low density fluid mixes with at least aportion of high density fluid.

17. The system of embodiment 16 wherein the system is configured suchthat at least a portion of low density fluid is removed from the highdensity fluid by separation.

18. The system of embodiment 17 wherein said separation comprisesreverse osmosis, or forward osmosis, or distillation, or evaporation, orgravitational separation, or decanting, or coalescing, or centrifuge, orfiltration, or cryodesalination, or freeze desalination, solventing out,or precipitation, or extraction, or extractive distillation.

19. The system of embodiment 2 wherein the low density fluid compriseswater and the high density fluid comprises brine.

20. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises a first and a second storageunit and wherein the system is configured such that the high densityfluid is stored within the first storage unit and the low density fluidis stored in the second storage unit.

21. The system of embodiment 20 wherein the high density fluid comprisesa liquid.

22. The system of embodiment 21 wherein the system is configured suchthat the first and the second storage unit are operably connected suchthat a gas is transferrable between the first and the second storageunit as liquid enters a unit and displaces the gas.

23. The system of embodiment 22 wherein the system is configured suchthat a semi-permeable barrier allows the transfer of gas whilepreventing the transfer of liquid.

24. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir is located under a body of water.

25. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir is at an elevation greater than thesurface of the body of water.

26. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises a floating structure.

27. The system of embodiment 1 further comprising a pressure exchanger.

28. The system of embodiment 27 wherein the system is configured suchthat the pressure exchanger is located at an elevation less than theelevation of the first storage reservoir and greater than or equal tothe elevation of the second storage reservoir.

29. The system of embodiment 1 wherein the low density fluid or highdensity fluid comprises desalinated water.

30. The system of embodiment 1 wherein the low density fluid or highdensity fluid comprises treated seawater.

Embodiments with a Subsea Pump and/or Generator

The present embodiments may pertain to fluid displacement energy storageemploying a subsea pump and/or subsea generator, or a pump and/orgenerator located near the lower elevation reservoir, or any combinationthereof.

Some embodiments may comprise a higher elevation reservoir and a lowerelevation reservoir. The higher elevation reservoir may have anelevation greater than or higher than the lower elevation reservoir. Thelower elevation reservoir may have an elevation lower than the higherelevation reservoir. One or more pipes may interconnect the higherelevation reservoir to the lower elevation reservoir. In someembodiments, the system may be designed to store a high density fluidand a low density fluid, wherein the high density fluid comprises ahigher density fluid than the density of the low density fluid.

In some embodiments, energy or power may be stored by transferring orpumping high density fluid from the lower elevation reservoir to thehigher elevation reservoir, displacing low density fluid from the higherelevation reservoir into the lower elevation reservoir. In someembodiments, energy or power may be generated by allowing high densityfluid from higher elevation reservoir to be transferred to the lowerelevation reservoir, displacing low density fluid in the lower elevationreservoir into the higher elevation reservoir. It may be desirable forthe volumetric flow rate of the low density fluid transferred betweenthe reservoirs to be about the same as the volumetric flow rate of thehigh density fluid transferred between the reservoirs. It may bedesirable for power to be generated from the high density fluid, or lowdensity fluid, or any combination thereof using a power recovery device,which may include, but are not limited to, a generator, or a turbine, ora reversible pump-generator, or a pressure exchanger, or a desalinationsystem or process, or any combination thereof.

In some embodiments, energy or power may be stored by transferring orpumping high density fluid from the lower elevation reservoir to thehigher elevation reservoir, while allowing low density fluid to betransferred from the higher elevation reservoir to the lower elevationreservoir. In some embodiments, energy or power may be generated byallowing high density fluid from the higher elevation reservoir to betransferred to the lower elevation reservoir, while allowing low densityfluid to be transferred from the lower elevation reservoir to the higherelevation reservoir. It may be desirable for the volumetric flow rate ofthe low density fluid transferred between the reservoirs to be about thesame as the volumetric flow rate of the high density fluid transferredbetween the reservoirs. It may be desirable for power to be generatedfrom the high density fluid, or low density fluid, or any combinationthereof using a power recovery device, which may include, but are notlimited to, a generator, or a turbine, or a reversible pump—generator,or a pressure exchanger, or a desalination system or process, or anycombination thereof.

In some embodiments, it may be desirable to locate the pump and/orgenerator near the lower elevation reservoir. For example, it may bedesirable for the pump and/or generate interconnected to a pipe at ornear the lower elevation reservoir. For example, it may be desirable forthe pump and/or generator to be fluidly connected to the high densityfluid. By placing the pump and/or generate at an elevation near theelevation of the lower elevation reservoir and/or locating the pumpand/or generator between the lower elevation reservoir and the higherelevation reservoir, it may be possible for the portion of the pumpand/or generator exposed to the fluid transferred between the pumpand/or generator and the higher elevation reservoir to be at a pressurenear the hydrostatic pressure of the high density fluid, while theportion of the pump and/or generator exposed to the fluid transferredbetween the pump and/or generator and the lower elevation reservoir maybe at a pressure near the hydrostatic pressure of the low density fluid,or near the hydrostatic pressure of the fluid body or water body orocean with which the lower elevation reservoir is immersed at theelevation of the lower elevation reservoir, or any combination thereof.By locating the pump and/or generating at an elevation near the lowerelevation reservoir, it may be possible for the lower elevationreservoir to operate with an internal fluid pressure or internalpressure near the pressure of the hydrostatic pressure of the body ofliquid or body of water adjacent to the lower elevation reservoir at ornear the elevation of the lower elevation reservoir, even if the highdensity fluid has a density greater than the density of the water, orseawater, or other liquid comprising the body of water or body ofliquid, or the density of the low density liquid, or any combinationthereof.

In some embodiments, it may be desirable for the low density fluid tocomprise a liquid. For example, in some embodiments, if the low densityfluid comprises a liquid, the volume of the low density fluid maynegligibly change or remain relatively constant in response to changesin pressure of the low density fluid. Due to, for example, the practicalincompressibility of liquids, employing a liquid as a low density fluidmay enable the lower elevation reservoir to comprise a rigid structure.Due to, for example, the practical incompressibility of liquids,employing a liquid as a low density fluid may enable high round tripenergy efficiency energy storage in a practically constant volumesystem. Due to, for example, the practical incompressibility of liquids,employing a liquid as a low density fluid may enable high round tripenergy efficiency energy storage in a system without requiring thermalstorage or storage of heat generated from the compression of a fluid.

In some embodiments, it may be desirable to employ a liquid with asimilar density to a body of liquid or body of water adjacent to orimmersing the lower elevation reservoir. For example, it may bedesirable to employ water, or treated seawater, or other liquid withsimilar density to the surrounding or adjacent water body as the lowdensity fluid to enable pressure inside the lower elevation reservoir tobe similar to, or close to, or as close as desired to the pressureoutside the lower elevation reservoir. For example, if the low densityfluid comprises treated seawater and the lower elevation reservoir isimmersed in ocean water or seawater of similar density to the lowdensity fluid, the hydrostatic pressure or elevation column pressure maybe similar inside and outside the lower elevation reservoir. The lowerthe pressure difference between the inside and outside of an reservoir,the lower the required pressure difference resistance or pressuredifference tolerance of the storage reservoir, and/or the lower therequired wall thickness, and/or the cost. For example, reducing thedesign pressure difference between the inside and outside of a reservoirmay enable lower cost of manufacturing, or lower material cost, or lowerinstallation cost, or any combination thereof of the lower elevationreservoir or tanks. For example, if the low density fluid is seawater,or water, or a fluid of similar density to the liquid in the adjacent orsurrounding body of water, the subsea reservoir or subsea reservoircomprising a subsea tank may be at or near the pressure of the adjacentwater body at the same elevation, for example, even if the tankcomprises a rigid structure or a closed rigid structure.

In some embodiments, a valve may be employed to control the pressure ofthe low density fluid, or high density fluid, or any combinationthereof. In some embodiments, if the pressure in the lower elevationreservoir, or pipe, or any combination thereof exceeds a thresholdvalue, a valve may open to allow low density fluid to be displaced intothe higher elevation reservoir. In some embodiments, if the pressure inthe lower elevation reservoir, or pipe, or any combination thereof isequal to or less than a threshold value, a valve may closed. The use ofa valve to manage pressure of the low density fluid may enable the useof low density fluids with densities different from the density of theliquid, or fluid, or body of liquid which the lower elevation reservoiris immersed. The use of a valve to manage pressure of the low densityfluid may enable the use of low density fluids with density less than orequal to the density of the liquid, or fluid, or body of liquid whichthe lower elevation reservoir is immersed. The use of a valve to managepressure of the low density fluid may enable the use of low densityfluids with density different than the density of the liquid, or fluid,or body of liquid which the lower elevation reservoir is immersed, whileenabling the internal pressure of the lower elevation reservoir to benear the pressure of the adjacent water body at the same elevation. Theuse of a valve to manage pressure of the low density fluid may enablethe use of low density fluids with density less than or equal to thedensity of the liquid, or fluid, or body of liquid which the lowerelevation reservoir is immersed, while enabling the internal pressure ofthe lower elevation reservoir to be near the pressure of the adjacentwater body at the same elevation.

In some embodiments, the high density fluid may be stored in separatestorage units from the low density fluid within the higher elevationreservoir. In some embodiments, the high density fluid may be stored inthe same storage units as the low density fluid within the higherelevation reservoir.

In some embodiments, the high density fluid may be stored in separatestorage units from the low density fluid within the lower elevationreservoir. In some embodiments, the high density fluid may be stored inthe same storage units as the low density fluid within the towerelevation reservoir.

In some embodiments, the higher elevation reservoir may be floating, orthe higher elevation reservoir may be on land, or the higher elevationreservoir may be subsea, or the higher elevation reservoir may belocated on the seabed subsea, or the higher elevation reservoir may belocated suspended or otherwise above the seabed subsea, or anycombination thereof.

In some embodiments, the lower elevation reservoir may be floating, orthe lower elevation reservoir may be on land, or the lower elevationreservoir may be subsea, or the lower elevation reservoir may be locatedon the seabed subsea, or the lower elevation reservoir may be locatedsuspended or otherwise above the seabed subsea, or any combinationthereof.

FIGS. 98-109 Summary

FIGS. 98-109 may show an energy storage system which may store power bychanging the elevation of a low density fluid and a high density fluid.Energy or power may be stored by raising the elevation of at least aportion of a high density fluid, while lowering the elevation of a leasta portion of a low density fluid. Energy or power may be generated bylowering the elevation of a high density fluid, while raising theelevation of a low density fluid. In some embodiments, the volumetricflow rate of low density fluid transferred between reservoirs may besimilar or about the same as the volumetric flow rate of high densityfluid transferred between reservoirs.

FIGS. 98-101 may show an embodiment where energy may be stored bypumping a high density fluid from a lower elevation reservoir to ahigher elevation reservoir, displacing low density fluid in the higherelevation reservoir and/or resulting in the transfer of low densityfluid from the higher elevation reservoir to the lower elevationreservoir. 98-101 may employ a valve to help control the pressure of thelow density fluid, which may be shown in or near the higher elevationreservoir in FIGS. 98-101 . In FIGS. 98-101 , the higher elevationreservoir may be floating on a body of water, while the lower elevationreservoir may be located under or immersed in the body of water. InFIGS. 98-101 , low density fluid and/or high density fluid may be storedin the same storage units in the higher elevation reservoir and thelower elevation reservoir.

FIGS. 102-105 may show an embodiment where energy may be stored bypumping a high density fluid from a lower elevation reservoir to ahigher elevation reservoir, displacing low density fluid in the higherelevation reservoir and/or resulting in the transfer of low densityfluid from the higher elevation reservoir to the lower elevationreservoir. 102-105 may employ a valve to help control the pressure ofthe low density fluid, which may be shown in or near the lower elevationreservoir in FIGS. 102-105 . In FIGS. 102-105 , the higher elevationreservoir may be floating on a body of water, while the lower elevationreservoir may be located under or immersed in the body of water. InFIGS. 102-105 , low density fluid and/or high density fluid may bestored in the same storage units in the higher elevation reservoir andthe lower elevation reservoir.

FIGS. 106-109 may show an embodiment where energy may be stored bypumping a high density fluid from a lower elevation reservoir to ahigher elevation reservoir, and/or allowing the transfer of low densityfluid from the higher elevation reservoir to the lower elevationreservoir. 106-109 may employ a valve to help control the pressure ofthe low density fluid. In FIGS. 106-109 , the higher elevation reservoirmay be floating on a body of water, while the lower elevation reservoirmay be located under or immersed in the body of water. In FIGS. 106-109, low density fluid and/or high density fluid may be stored in separatestorage units in the higher elevation reservoir and the lower elevationreservoir.

Example FIGS. 98-105 Key

Example FIGS. 98-105 Key Label Description 1 ‘1’ may comprise a higherelevation reservoir. ‘1’ may be configured to store low density fluidand high density fluid. 2 ‘2’ may comprise a lower elevation reservoir.‘2’ may be configured to store low density fluid and high density fluid.3 ‘3’ may comprise a low density fluid pipe, which may be configured totransfer low density fluid between the higher elevation reservoir andlower elevation reservoir. A valve may be connected to the low densityfluid pipe to control the pressure of the low density fluid pipe. Forexample, the valve may open to allow an increase in pressure of thelower elevation reservoir or pipe. For example, the valve may close toallow an increase in pressure of the lower elevation reservoir or pipe.For example, the valve may open to allow a reduction in pressure of thelower elevation reservoir or pipe. For example, the valve may dose toallow a reduction in pressure of the lower elevation reservoir or pipe.4 ‘4’ may comprise a segment of pipe transferring high density fluidbetween the lower elevation reservoir and the pump, or generator, orpressure exchanger, or power recovery device, or desalination system orprocess, or any combination thereof. In some embodiments, ‘4’ may be ata lower pressure than ‘6’ where ‘6’ is at the same elevation as ‘4’. 5‘5’ may comprise a pump, or generator, or pressure exchanger, or powerrecovery device, or desalination system or process, or any combinationthereof. ‘5’ may be configured to pump high density fluid, and/orgenerate power from high density fluid, or any combination thereof. 6‘6’ may comprise a segment of pipe transferring high density fluidbetween the pump, or generator, or pressure exchanger, or power recoverydevice, or desalination system or process, or any combination thereofand a higher elevation reservoir. In some embodiments, ‘6’ may be at ahigher pressure than ‘4’ at the same elevation as ‘4’. 7 ‘7’ maycomprise a vessel or platform which the higher elevation reservoir islocated. In some embodiments, ‘7’ may be floating on a body of water. V‘V’ may comprise a valve, or flow controller, or pump, or power recoverydevice, or any combination thereof. ‘V’ may be interconnected to the lowdensity fluid, or high density fluid, or any combination thereof. ‘V’may be employed to control the flow rate of fluid, or pressure of fluid,or any combination thereof. In some embodiments, ‘V’ may beinterconnected with the low density fluid to control the pressure of thelow density fluid. In some embodiments, ‘V’ may be located at anyelevation. In some embodiments, ‘V’ may be located on or interconnectedto or fluidly connected to a pipe between the higher elevation reservoirand/or the lower elevation reservoir. Seabed Land located underneath orsubmerged in a body of water. Ocean A body of liquid wherein which theenergy storage system or process may be located. High A fluid with adensity greater than, the low density fluid. Density Fluid Low A fluidwith a density lower than the high density fluid. Density FluidElectricity Power transferred to or from the energy storage system orprocess.

Example FIGS. 106-109 Key

Example FIGS. 106-109 Key Label Description 1 ‘1’ may comprise a higherelevation reservoir. ‘1’ may be configured to store low density fluidand high density fluid in separate storage units. 2 ‘2’ may comprise alower elevation reservoir. ‘2’ may be configured to store low densityfluid and high density fluid in the same storage units, or separatestorage units, or any combination thereof. 3 ‘3’ may comprise a lowdensity fluid pipe, which may be configured to transfer low densityfluid between the higher elevation reservoir and lower elevationreservoir. A valve may be connected to the low density fluid pipe tocontrol the pressure of the low density fluid pipe. For example, thevalve may open to allow an increase in pressure of the lower elevationreservoir or pipe. For example, the valve may close to allow an increasein pressure of the lower elevation reservoir or pipe. For example, thevalve may open to allow a reduction in pressure of the lower elevationreservoir or pipe. For example, the valve may close to allow a reductionin pressure of the lower elevation reservoir or pipe. 4 ‘4’ may comprisea pump, or generator, or pressure exchanger, or power recovery device,or desalination system or process, or any combination thereof. ‘4’ maybe configured to pump high density fluid, and/or generate power fromhigh density fluid, or any combination thereof. 5 ‘5’ may comprise asegment of pipe transferring high density fluid between the pump, orgenerator, or pressure exchanger, or power recovery device, ordesalination system or process, or any combination thereof and a higherelevation reservoir. 6 ‘6’ may comprise a vessel or platform which thehigher elevation reservoir is located. In some embodiments, ‘6’ may befloating on a body of water. V ‘V’ may comprise a valve, or flowcontroller, or pump, or power recovery device, or any combinationthereof. ‘V’ may be interconnected to the low density fluid, or highdensity fluid, or any combination thereof. ‘V’ may be employed tocontrol the flow rate of fluid, or pressure of fluid, or any combinationthereof. In some embodiments, ‘V’ may be interconnected with the lowdensity fluid to control the pressure of the low density fluid. In someembodiments. ‘V’ may be located at any elevation. In some embodiments,‘V’ may be located on or interconnected to or fluidly connected to apipe between the higher elevation reservoir and/or the lower elevationreservoir. Seabed Land located underneath or submerged in a body ofwater. Ocean A body of liquid wherein which the energy storage system orprocess may be located. High A fluid with a density greater than the lowdensity fluid. Density Fluid Low A fluid with a density lower than thehigh density fluid. Density Fluid Electricity Power transferred to orfrom the energy storage system or process.

Example Exemplary Embodiments

A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump;

wherein the pump and the first and the second reservoir are operativelyconnected such that power is stored by displacing the first fluid in thefirst storage reservoir by pumping the second fluid from the secondstorage reservoir to the first storage reservoir and such that power isgenerated by allowing the pumped second fluid in the first storagereservoir to return to the second reservoir; and

wherein the first fluid is a liquid.

Notes

Note: In some embodiments, one or more power generation devices may belocated near the lower elevation reservoir and/or may be fluidlyconnected to the high density fluid, or low density fluid, or anycombination thereof. For example, power generation devices may include,but are not limited to, one or more or any combination of the following:a pump, or a generator, or a turbine, or a pressure exchanger, or apower recovery device, or a power exchanger, or a desalination process,or a semi-permeable membrane, or a reverse osmosis process, or amembrane distillation process, or a separation process. In someembodiments, a reverse osmosis or other semi-permeable membranedesalination process may be interconnected or fluidly connected to thelow density fluid pipe or low density fluid. For example, in someembodiments, it may be desirable for the system to pressurize the lowdensity fluid using, for example, a pump, or generator, or valve, or thehigh density fluid, or any combination thereof, wherein at least aportion of the pressure of the low density fluid may be converted topower or harnessed by transferring at least a portion of the low densityfluid through a pressure exchanger or a power recovery device, which maytransfer the power or pressure to a desalination feed, which may betransferred into a desalination process or system, such as a reverseosmosis process or system, or nanofiltration process or system. Forexample, in some embodiments, the low density fluid may compriseseawater, or treated seawater, or any combination thereof. For example,in some embodiments, it may be desirable for the system to pressurizethe low density fluid using, for example, a pump, or generator, orvalve, or the high density fluid, or any combination thereof, wherein atleast a portion of the pressure of the low density fluid may beconverted to power or harnessed by transferring at least a portion ofthe low density fluid into a desalination process or system, such as areverse osmosis process or system, or nanofiltration process or system.In some embodiments, it may be desirable to locate at least a portion ofthe desalination, or at least the membrane portion of the desalinationsystem or process, near the lower elevation reservoir, or at a lowerelevation. For example, by placing a desalination system or process at alower elevation relative to the elevation of the desalination feed, thedensity difference between the desalinated water and the desalinationfeed may result in a hydrostatic pressure difference which may provideat least a portion of a driving force or otherwise facilitate thepowering of desalination. The greater the elevation difference betweenthe elevation of the desalination process and the elevation of thedesalination feed source, the greater the force or pressure supplied bythe hydrostatic pressure difference between the desalinated water andthe desalination feed due to the density difference between thedesalinated water and the desalination feed, which may significantlyreduce the thermodynamic minimum required applied power or pressure orenergy to desalinate at least a portion of the desalination feed water.For example, in some embodiments, to achieve the energy efficiency orreduction in required power or pressure, the desalination retentate orconcentrate must be discharged at a lower elevation or an elevation nearthe elevation of the desalination process.

Embodiments Employing Density Differentials to Facilitate PowerGeneration and Desalination

Background

Desalination is energy intensive. Desalinating seawater using reverseosmosis generally requires greater than 2 kWh electricity or power perm3 of freshwater permeate produced. The thermodynamic minimum energyrequirement to produce freshwater from seawater is about 1 kWh per m³.Generally, the minimum thermodynamic energy consumption of desalinationinvolves the energy required to produce the pressure difference requiredto overcome the osmotic pressure of the desalination feed. Seawater hasan osmotic pressure of about 27 Bar. Generally, desalination may occurwhen a pressure equal to or greater than the osmotic pressure of thedesalination feed water, such as seawater, is applied to thedesalination feed water in the presence of a semipermeable membrane,wherein the desalination membrane has a first side and a second side,wherein the pressure difference between the first side of the membraneand the second side of the membrane may be greater than or equal to theosmotic pressure of the desalination feed water. It may be desirable forthe desalination feed water to be located on the first side or the sidewith the greater pressure and/or it may be desirable for the pressureapplied to the first side is applied with the desalination feed water.

Reverse osmosis desalination generally comprises a feed desalinationwater input and a semi-permeable membrane, wherein the pressure of thefeed desalination water against the desalination membrane results in thepermeation of water through the membrane and the rejection of at least aportion of the dissolved salts, forming a ‘permeate’ lower salinitystream on the opposite side of the membrane from the desalination feedwater and a higher salinity concentrate or retentate stream.

SUMMARY OF INVENTION

Some embodiments of the present invention may pertain to desalinationfacilitated by or at least partially powered by the difference ingravitational hydrostatic pressure between desalination feed anddesalinated water in a liquid column. Some embodiments of the presentinvention may pertain to the generation of power from the discharge orrelease of desalination retentate, or concentration, or brine effluentin a liquid column due to, for example, the difference in gravitationalhydrostatic pressure between desalination retentate, or concentration,or brine effluent and seawater in a liquid column.

DETAILED DESCRIPTION

The present invention pertains to desalination. The present inventionmay pertain to a lower energy consumption or greater energy efficiencysystem or process for desalination. The present invention may pertain toa system or process for desalinating wherein desalination is facilitatedby the difference in density between freshwater and desalination feed,such as seawater. The present invention may pertain to a system orprocess for desalinating wherein desalination is facilitated by thedifference in hydrostatic pressure between desalinated water anddesalination feed in a liquid column which may be driven by the densitydifference between higher salinity desalination feed, such as seawater,and lower salinity desalinated water, such as freshwater.

Some embodiments may comprise a first liquid column and a second liquidcolumn, wherein the first liquid column comprises desalination feed andthe second liquid column comprises desalinated water. In someembodiments, at least a portion of a desalination process may be locatedat an elevation lower than the elevation of the highest elevationportion of the first column and/or the highest elevation portion of thesecond column. In some embodiments, it may be desirable for at least aportion of a desalination process to be located at a lower elevationportion of the first column, or second column, or any combinationthereof. In some embodiments, the desalinating step, such as, forexample, the reverse osmosis membrane, may be located at the deepest orlowest practical elevation of the first liquid column, or second liquidcolumn, or any combination thereof. In some embodiments, the firstliquid column may be connected or fluidly connected to the desalinatingstep and the second liquid column may be connected or fluidly connectedto the desalinating step. In some embodiments, the first liquid columnmay be separated from the second liquid column by the desalinating step,which may comprise a desalination membrane, such as a reverse osmosismembrane. At any given traversed elevation or depth, the liquid in thefirst liquid column may have a different hydrostatic pressure than theliquid in the second liquid column due to the difference in densitybetween the liquid in the first column and the liquid in the secondcolumn. At its natural state, a desalinating step, which may be locatedat an elevation lower than the maximum elevation of the first liquidcolumn and second liquid column and fluidly connected to the liquid inthe first liquid column and the liquid in the second liquid column, mayexperience a pressure difference between portions in contact with thefirst liquid column and portions in contact with the second liquidcolumn. At its natural state, a reverse osmosis membrane, which may belocated at an elevation lower than the maximum elevation of the firstliquid column and second liquid column and fluidly connected to theliquid in the first liquid column and the liquid in the second liquidcolumn, may experience a pressure difference between the side of themembrane in contact with the first liquid column and the side of themembrane in contact with the second liquid column. The natural statehydrostatic pressure difference between the first liquid column and thesecond liquid column may be dependent on the density difference betweenthe liquid in the first liquid column and the liquid in the secondliquid column, and the traversed elevation or depth of the first liquidcolumn and the second liquid column. In some embodiments, the naturalstate hydrostatic pressure difference between the first liquid columnand second liquid column may be lower than the osmotic pressure of thedesalination feed, however the pressure difference may be sufficient tosignificantly reduce the required applied pressure, or applied power, orenergy, or any combination thereof required to at least partiallydesalinate desalination feed. For example, the hydrostatic pressure ofthe first liquid column comprising desalination feed may be greater thanthe hydrostatic pressure of the second liquid column comprisingdesalinated water because of the density difference between thedesalination feed and desalinated water. Some embodiments may involveincreasing the pressure in the first liquid column to a pressure greaterthan the hydrostatic pressure, or reducing the pressure of the secondliquid column to a pressure less than the hydrostatic pressure, or anycombination thereof to enable a pressure difference across thedesalination step or reverse osmosis membrane sufficient to overcome theosmotic pressure of the desalination feed and enable desalination. Someembodiments may employ, for example, including, but not limited to, apump, or pressure exchanger, or fluid displacement, or any combinationthereof to increase pressure, or reduce pressure, or any combinationthereof. In some embodiments, to achieve potential energy efficiencybenefits, it may be desirable to release desalination retentate orconcentrate at an elevation less than the maximum elevation of the firstwater column, or the second water column, or any combination thereof. Insome embodiments, to achieve potential energy efficiency benefits, itmay be desirable to release desalination retentate or concentrate at thelowest possible, or practical, or desirable elevation. In someembodiments, the lower the elevation which the desalination retentate orconcentrate is discharged or released, the lower the energy or powerwhich must be expended to discharge or release said desalinationretentate or concentrate. In fact, in some embodiments, power may begenerated from the discharging of desalination retentate or concentrate.For example, if the elevation of the desalination system or processproducing the desalination retentate or concentrate is higher than theelevation which the desalination retentate or concentrate is dischargedand/or the density of the desalination retentate or concentrate isgreater than the density of the adjacent or surrounding liquid body, thedesalination retentate or concentrate may possess kinetic energy, orpotential energy, or may generate power.

The density of seawater is generally 1.02 g/mL-1.035 g/mL, with the mostcommon density seawater density generally between 1.025 g/mL-1.028 g/mL.The density of freshwater is about 1 g/mL. In semi-permeable membranebased desalination processes, such as reverse osmosis, the desalinationfeed water stream generally possesses a greater salinity than thedesalination permeate and a lower salinity than the desalinationconcentrate or retentate. For example, a desalination process with 40%recovery may comprise a desalination feed water comprising a salinity of35 g/L and a density of 1.025 kg/L, or a desalination permeate ordesalinated water comprising a salinity of municipal freshwater and adensity of 1 kg/L, or a desalination concentrate or retentate comprisinga salinity of 58.3 g/L and a density of 1.04 kg/L, or any combinationthereof.

In some embodiments, a desalination system or process may be located atan elevation higher than the lowest possible or lowest practicalelevation within a water body. For example, a desalination system orprocess or a desalination step may be located floating on the surface ofwater body. For example, a desalination system or process or adesalination step may be located beneath the surface of a water body,however above the lowest possible or lowest practical elevation within awater body. For example, a desalination system or process or adesalination step may be located beneath the surface of a water body,however above the seafloor. In some embodiments, it may be desirable toplace the seawater intake or desalination feed intake at an elevationabove the seafloor and below the surface of the water body to minimizepotential particulates, or scaling, or fouling, or sediment, orturbidity, or seafloor disturbance, or any combination thereof from themovement of seawater or desalination feed into the desalination systemor process.

Natural Difference in Hydrostatic Pressure Between Freshwater andSeawater from the Density Difference Between Freshwater and Seawateracross a Liquid Column Liquid Column Hydrostatic Pressure DifferencePressure Difference Vertical Pressure as a Percentage of as a Percentageof Elevation Difference Seawater Osmotic Typical RO Applied (meters)(Bar) Pressure Pressure Difference 500 1.28 4.72% 1.82% 1000 2.55 9.45%3.64% 1500 3.83 14.17% 5.47% 2000 5.10 18.90% 7.29% 2500 6.38 23.62%9.11% 3000 7.65 28.34% 10.93% 3500 8.93 33.07% 12.76% 4000 10.20 37.79%14.58% 4500 11.48 42.52% 16.40% 5000 12.76 47.24% 18.22% 5500 14.0351.97% 20.04% 6000 15.31 56.69% 21.87% 6500 16.58 61.41% 23.69% 700017.86 66.14% 25.51% 7500 19.13 70.86% 27.33% 8000 20.41 75.59% 29.15%8500 21.68 80.31% 30.98% 9000 22.96 85.03% 32.80% 9500 24.23 89.76%34.62% 10000 25.51 94.48% 36.44% 10500 26.79 99.21% 38.27% 11000 28.06103.93% 40.09% 11500 29.34 108.65% 41.91% 12000 30.61 113.38% 43.73%

The above table uses a recovery ratio of 40% to determine the typical ROapplied pressure difference of 70 Bar pressure. In some embodiments, itmay be desirable to employ a lower recovery ratio, such as a recoveryratio of less than 40%. For example, it may be desirable to employ alower recovery ratio because the cost or energy involved withpre-treatment may be lower due to the lower concentration ofparticulates, or fouling agents, or scalants in open water, or deeperwater, or offshore, or any combination thereof. A lower recovery ratiomay reduce the required applied pressure, which may reduce the requiredapplied power and/or increase the ‘Pressure Difference as a Percentageof Typical RO Applied Pressure Difference’ of the natural hydrostaticpressure difference between freshwater and seawater, significantlyreducing power requirements and energy consumption.

As shown in the above table, depending of the water depth or theelevation difference of the liquid column, the natural hydrostaticpressure difference between freshwater and seawater may significantlyreduce the required applied pressure for desalination. For example, a3,000 meter liquid column or 3,000 meter water depth, the naturalhydrostatic pressure difference between freshwater and seawater providesabout 27.78% of the osmotic pressure of seawater, which may mean thenatural hydrostatic pressure difference between freshwater and seawatermay reduce the theoretical minimum applied power requirement or appliedenergy requirement for desalination by about 27.78%. In someembodiments, with liquid columns greater than about 10,800 meters, thenatural hydrostatic pressure difference between freshwater and seawatermay be about equal to or greater than the osmotic pressure of seawater,which may mean it is possible for desalination to be powered from thenatural hydrostatic pressure difference between freshwater and seawaterand may not require significant additional applied power or pressure.

In some embodiments, a desalination system or process may be located atan elevation higher than the lowest possible or lowest practicalelevation within a water body. In some embodiments, the desalinationsystem or process may transform or separate intake desalination feed,which may comprise seawater, into desalination permeate, which maycomprise desalinated water, and desalination concentrate or retentate,which may comprise a higher salinity than the desalination feed, whereinthe density and/or salinity for the desalination concentrate orretentate is greater than the density and/or salinity of thedesalination feed, or seawater, or any combination thereof. In someembodiments, power may be generated from the desalination retentate orconcentrate. For example, in some embodiments, desalination retentate orconcentrate may be transferred into a liquid column comprisingdesalination retentate or concentrate which traverses a difference inelevation, wherein the lowest elevation point or deepest point of theliquid column exhibits a hydrostatic pressure greater than thehydrostatic pressure of the adjacent water body or seawater body at thesame elevation or depth. For example, in some embodiments, desalinationretentate or concentrate may be transferred into a liquid columncomprising desalination retentate or concentrate which traverses adifference in elevation, wherein the lowest elevation point or deepestpoint of the liquid column exhibits a hydrostatic pressure greater thanthe hydrostatic pressure of the adjacent water body or seawater body atthe same elevation or depth, due to, for example, the density differencebetween desalination retentate or concentrate and the liquid comprisingthe adjacent water body, such as, for example, seawater.

For example, in some embodiments, the liquid column comprisingdesalination retentate or concentrate may comprise a pipe, wherein thehigher elevation end of the pipe is located at or near or may beconnected to the desalination system or process and the lower elevationend of the pipe may be located at an elevation significantly lower thanthe elevation of the desalination system or process. A hydraulicgenerator or other power recovery device may be located on or fluidlyconnected to the pipe or liquid column. In some embodiments,desalination retentate or concentrate may enter the higher elevation endof the pipe or liquid column and exit the lower elevation end of thepipe or liquid column, wherein power is generated from the flow ofdesalination retentate or concentrate. Power or energy may be generateddue to the gravitational potential energy from the difference in densitybetween the desalination retentate or concentrate and the adjacentseawater or adjacent body of water and the difference in elevationbetween the higher elevation end and lower elevation end of the liquidcolumn.

In some embodiments, the concentration of the retentate or concentratemay be increased, or a greater density brine may be sourced from anothersource, or any combination thereof which may increase the potentialpower density, or hydrostatic pressure difference, or power output fromthe liquid column. For example, the retentate or concentrate may beconcentrated with evaporation. For example, seawater may be concentratedusing evaporation. For example, the greater the density differencebetween the higher density liquid and the seawater or other liquid inthe water body, the greater the potential hydrostatic pressuredifference and/or the greater the potential and/or the greater thepotential power output for the same volumetric flow rate in the sameelevation difference or vertical column of the liquid column.

Natural Difference in Hydrostatic Pressure Between DesalinationConcentrate and Seawater from the Density Difference BetweenDesalination Concentrate and Seawater across a Liquid Column and thePotential Energy Output per m3 of Concentrate Energy Energy LiquidEnergy Generated as a Generated Column Hydrostatic Generated Percentageof as a Vertical Pressure per m3 of Theoretical Percentage ElevationDifference Concentrate Minimum RO of Typical (meters) (Bar) (kWh) EnergyRO Energy 500 0.765 0.020 3.06% 1.39% 1000 1.531 0.041 6.13% 2.78% 15002.296 0.061 9.19% 4.18% 2000 3.061 0.082 12.25% 5.57% 2500 3.827 0.10215.31% 6.96% 3000 4.592 0.123 18.38% 8.35% 3500 5.357 0.143 21.44% 9.74%4000 6.122 0.163 24.50% 11.14% 4500 6.888 0.184 27.56% 12.53% 5000 7.6530.204 30.63% 13.92% 5500 8.418 0.225 33.69% 15.31% 6000 9.184 0.24536.75% 16.70% 6500 9.949 0.265 39.81% 18.10% 7000 10.714 0.286 42.88%19.49% 7500 11.480 0.306 45.94% 20.88% 8000 12.245 0.327 49.00% 22.27%8500 13.010 0.347 52.06% 23.66% 9000 13.776 0.368 55.13% 25.06% 950014.541 0.388 58.19% 26.45% 10000 15.306 0.408 61.25% 27.84% 10500 16.0710.429 64.31% 29.23% 11000 16.837 0.449 67.38% 30.63% 11500 17.602 0.47070.44% 32.02% 12000 18.367 0.490 73.50% 33.41%

The above table employs an example reverse osmosis energy consumption of2.2 kWh per m³ of permeate and a recovery ratio of about 40% for thetypical reverse osmosis system. Using the example in the above table, a100 MW desalination plant next to a 3,000 meter liquid column mayreceive about 8.35 MW of power from desalination concentrate transferredinto the liquid column in a scenario where the desalination plantoperates at 2.2 kWh per m³ of permeate, or may receive about 18.38 MW ofpower from desalination concentrate transferred into the liquid columnin a scenario where the desalination plant operates at 1 kWh per m³ ofpermeate.

Example FIG. 110 Key

Example FIG. 110 Key Label Description 1 ‘1’ may comprise a seawaterintake or desalination Intake pipe or riser. ‘1’ may transfer seawaterfrom the water body into a pre-treatment step or otherwise into thedesalination system or process. It may be desirable for ‘1’ to draw orintake seawater from a depth of significant depth, or a depth whereinturbidity or particulate concentrations are lower than the ocean or seaor other water body surface. For example, it may be desirable for ‘1’ todraw or intake seawater from a water depth greater than 50 meters, or100 meters, or 150 meters, or 200 meters, or 250 meters, or 300 meters,or 350 meters, or 400 meters, or 450 meters, or 500 meters, or 550meters. 2 ‘2’ may comprise desalination feed after pre-treatment and/orbefore pressurization with a pump or pressure exchanger or powertransfer device. 3 ‘3’ may comprise a pump, or pressure exchanger, orpower transfer device, or any combination thereof. ‘3’ may pressurize orapply pressure to the desalination feed and/or transfer the desalinationfeed into a pipe or transfer to transfer the desalination feed to alower elevation reverse osmosis step, or pressure driven desalinationstep, or any combination thereof. 4 ‘4’ may comprise a pipe or risertransferring pressurized desalination feed from a higher elevationregion or a pump in a higher elevation region to a desalination step,such as a reverse osmosis desalination step, in a lower elevationregion. 5 ‘5’ may comprise discharge of desalination concentrate orretentate or brine effluent. ‘5’ may comprise a discharge pipe ordischarge outlet. It may be desirable to discharge the desalinationconcentrate or retentate or brine at an elevation at, or near, or lowerthan the elevation of the desalination process to minimize energyconsumption associated with the discharging. In some embodiments, powermay be generated from discharging the desalination concentrate orretentate or effluent brine if, for example, the desalinationconcentrate or retentate or effluent brine is discharged at a lowerelevation than the elevation of the desalination step, or reverseosmosis system or process, or any combination thereof. 6 ‘6’ maycomprise desalinated water or desalination permeate. ‘6’ may comprise alower salinity than the salinity of ‘4’. ‘6’ may comprise a pipe orriser. ‘6’ may transfer desalination permeate from a desalination stepor reverse osmosis system or process at a lower elevation region to apost treatment step or to storage or to transfer to an application orany combination thereof at a higher elevation region. 7 ‘7’ may comprisedesalinated water after a Post treatment step. ‘7’ may comprisetransferring desalinated water from a post treatment step to a storageunit or storage facility or storage reservoir for desalinated water orfreshwater, or to an application, or any combination thereof. 8 ‘8’ maycomprise a storage unit or storage facility or storage reservoir fordesalinated water or freshwater. 9 ‘9’ may comprise a floating vesselhousing a portion of the system or process. In the present embodiment,‘9’ may comprise a vessel with the pre-teatment step, or the pump orpower transfer device, or the post treatment step, or the desalinatedwater storage unit or storage facility or storage reservoir, or anycombination thereof. ‘9’ may be moored. ‘9’ may be attached to adetachable or disconnectable mooring system. In some embodiments, ‘9’may produce hydrogen or other chemicals from the desalinated water. Insome embodiments, ‘9’ may transfer the desalinated water to a vessel orship, or in a pipeline, or any combination thereof to an application.Pre ‘Pre’ may comprise a pre-tteatmenf step. ‘Pre’ may comprise removingdissolved gases from the seawater intake. ‘Pre’ may comprise addingadditives, or filtration, or coagulation, or separation, or othertreatment, or desalination pre-treatments known in the art, or anycombination thereof. It may be advantageous to locate ‘Pre’ in anaccessible location or on a floating vessel to enable maintenance and/orto reduce energy consumption associated with depressurization and/orremoval of dissolved gases. RO ‘RO’ may comprise a reverse osmosisdesalination system or process, or may comprise a reverse osmosismembrane module, or may comprise a membrane separation process, or maycomprise a pressure difference driven desalination system, or process,or any combination thereof. It may be desirable to locate ‘RO’ at alower elevation than the elevation of the seawater intake, or thehighest elevation point of the liquid column, or the highest elevationpoint of ‘4’ or the highest elevation point of ‘6’, or any combinationthereof to benefit from the energy efficiency and supplied powerbenefits of the natural hydrostatic pressure difference between a liquidcolumn comprising desalination feed and a liquid column comprisingdesalinated water or freshwater. In some embodiments, it may bedesirable to locate ‘RO’ at the lowest possible, or desirable, orpractical elevation. In some embodiments, ‘RO’ may be located on theseabed or seafloor. In some embodiments, ‘RO’ may be suspended ortethered or otherwise located above the seafloor. In some embodiments,it may be desirable for ‘RO’ to be located beneath the surface of a bodyof water or a body of liquid. Post ‘Post’ may comprise a post treatmentstep. In some embodiments, ‘Post’ may comprise adding or removing salts,or biocides, or minerals, or other potential chemicals required for someapplications. In some embodiments, ‘Post’ may comprise desalinationpost-treatment systems and methods known in the art. In someembodiments, desalinated water may bypass ‘Post’ or otherwise betransferred into ‘8’ if, for example, ‘Post’ is unnecessary orundesired. Electricity ‘Electricity’ may comprise a power source. Insome embodiments, ‘Electricity’ may comprise power supplied from anexternal source, or may comprise power supplied from an internal source,or may comprise power supplied from an offshore source, or may comprisepower supplied by an onshore source, or may comprise power supplied fromthe discharging of desalination retentate or concentrate, or anycombination thereof. Ocean ‘Ocean’ may comprise a body of water, whichmay include, but is not limited to, an ocean, or sea, or bay, orestuary, or lake, or any combination thereof. Seabed ‘Seabed’ maycomprise the seafloor or land located, at or near the bottom of a bodyof water or body of liquid.

FIG. 111

FIG. 111 may comprise the same embodiment as FIG. 110 , except may showa riser and/or pipeline for transferring desalinated water or freshwateror post-treatment water to an application, or to an offshoreapplication, or to an onshore application, or any combination thereof.

FIG. 112

FIG. 112 may comprise the same embodiment as FIG. 111 , except may showa subsea storage reservoir for, for example, storing desalinated water.

FIG. 113

FIG. 113 may comprise the same embodiment as FIG. 112 , except may showa Post treatment step located in a lower elevation region.

FIG. 114

FIG. 114 may comprise the same embodiments as FIG. 112 , except may showthe reverse osmosis system or process, or reverse osmosis membrane, ordesalination membrane module, or other desalination step, or anycombination thereof located at an elevation higher than the elevation ofthe seabed and lower than the elevation of the surface of the body ofwater, or the source of desalination feed, or the pump, or thepretreatment, or the post treatment, or any combination thereof.

FIG. 115

FIG. 115 may comprise the same embodiments as FIG. 110 , except may showthe reverse osmosis system or process, or reverse osmosis membrane, ordesalination membrane module, or other desalination step, or anycombination thereof located at an elevation higher than the elevation ofthe seabed and lower than the elevation of the surface of the body ofwater, or the source of desalination feed, or the pump, or thepretreatment, or the post treatment, or any combination thereof.

FIG. 116

FIG. 116 may comprise the same embodiments as FIG. 111 , except may showthe reverse osmosis system or process, or reverse osmosis membrane, ordesalination membrane module, or other desalination step, or anycombination thereof located at an elevation higher than the elevation ofthe seabed and lower than the elevation of the surface of the body ofwater, or the source of desalination feed, or the pump, or thepretreatment, or the post treatment, or any combination thereof.

FIG. 117

FIG. 117 may comprise the same embodiments as FIG. 113 , except may showthe reverse osmosis system or process, or reverse osmosis membrane, ordesalination membrane module, or other desalination step, or anycombination thereof located at an elevation higher than the elevation ofthe seabed and lower than the elevation of the surface of the body ofwater, or the source of desalination feed, or the pump, or thepretreatment, or the post treatment, or any combination thereof,

FIG. 118 Summary

FIG. 118 may relate to a desalination system or process facilitated byor at least partially powered by the difference in hydrostatic pressurebetween freshwater or desalinated water and seawater or desalinationfeed across a liquid column, or a across an elevation, or between alower elevation region and a higher elevation region, or any combinationthereof. The present embodiment may be further facilitated by or poweredby reducing the pressure of desalination feed water to a pressure lowerthan the hydrostatic pressure of the freshwater or the desalinatedwater. In some embodiments, a subsea vessel or tank may be positioned orlocated at a depth or elevation equal to or greater than thesupplemental additional hydraulic head or reduction in hydraulic headpressure required to drive reverse osmosis desalination. For example, insome embodiments, said subsea vessel or tank may comprise a low pressuretank or pump-out tank, wherein a pump or other liquid transfer devicemay pump or otherwise transfer water from said subsea vessel or tank,which may result in the internal pressure of the subsea tank to besubstantially lower than the hydrostatic pressure at the water depth, orthe natural hydrostatic pressure of the desalinated water, or anycombination thereof. By locating the pump and/or the low pressure tankat a significantly higher elevation than the reverse osmosis module, thesystem or process may be at least partially powered by the difference innatural hydrostatic pressure between seawater and desalinated wateracross the liquid column comprising the elevation difference between thereverse osmosis module and the pump and/or low pressure tank. Bylocating the pump and/or the low pressure tank at a significantly higherelevation than the reverse osmosis module and allowing the reverseosmosis module to discharge desalination concentrate, or retentate, oreffluent brine at an elevation near, or equal to, or less than theelevation of the reverse osmosis module, the system or process may be atleast partially powered by or driven by the difference in naturalhydrostatic pressure between seawater and desalinated water across theliquid column comprising the elevation difference between the reverseosmosis module and the pump and/or low pressure tank. By locating thepump and/or the low pressure tank at a significantly higher elevationthan the reverse osmosis module, the pump and/or low pressure tank maybe more accessible for maintenance.

In some embodiments, the lower pressure tank may be located at anelevation lower than the elevation of the pump. In some embodiments, thepressure inside the lower pressure tank may be different from thenatural hydrostatic pressure of the desalinated water by a pressuredifference required or desired for reverse osmosis. In some embodiments,the lower pressure tank may be located adjacent to or at a similarelevation as the reverse osmosis module. In some embodiments,pre-treatment may be conducted before transferring the desalination feedinto the reverse osmosis process.

Example FIG. 118 Key

Example FIG. 118 Key Label Description 1 ‘1’ may comprise seawaterintake or desalination feed intake. It may be desirable for ‘1’ to belocated in a lower elevation region, which may be at a substantiallylower elevation than the elevation of the pump. In some embodiments, ‘1’may be located at an elevation or in a location within a body of waterwith low turbidity, which may minimize the required pre-treatment, ifany. In some embodiments, ‘1’ may be transferred to the surface or to ahigher elevation region for pre-treatment, or to remove at least aportion of dissolved gases, or any combination thereof, and thentransferred to the reverse osmosis step or other desalination step. 2‘2’ may comprise discharge of desalination concentrate or retentate orbrine effluent. ‘2’ may comprise a discharge pipe. It may be desirableto discharge the desalination concentrate or retentate or brine at anelevation at, or near, or lower than the elevation of the desalinationprocess to minimize energy consumption associated with the discharging.In some embodiments, power may be generated from discharging thedesalination concentrate or retentate or effluent brine if, for example,the desalination concentrate or retentate or effluent brine isdischarged at a lower elevation than the elevation of the desalinationstep, or reverse osmosis system or process, or any combination thereof.3 ‘3’ may comprise desalinated water, or freshwater, or any combinationthereof. ‘3’ may transfer desalinated water, or freshwater, or anycombination thereof to a medium elevation region or a higher elevationregion. ‘3’ may transfer desalinated water, or freshwater, or anycombination thereof from a reverse osmosis step or desalination step toa lower pressure tank, or a pump, or any combination thereof. In someembodiments, the elevation difference between the desalinated waterentering ‘3’ and the desalinated water exiting ‘3’ may comprise theelevation difference or column related to the natural hydrostaticpressure difference or gravitational hydrostatic pressure differencewhich may power at least a portion of desalination. 4 ‘4’ may comprise alow pressure tank, or a pump-out tank, or pump-out vessel. ‘4’ maycomprise a vessel with a lower internal pressure than the gravitationalhydrostatic pressure. ‘4’ may be operated such that the pressuredifference between the internal pressure of ‘4’ and the natural orgravitational hydrostatic pressure is sufficient to provide theadditional power or pressure required or desired to drive, orfacilitate, or enable desalination. In some embodiments, ‘4’ may belocated at a higher elevation than the desalination step or reverseosmosis step. The elevation or depth of the lower elevation tank mayinfluence or correlate with the potential reduction in pressure orpressure difference provided by the low pressure tank to drivedesalination. For example, if the low pressure tank is located at a 450meter depth, the potential increase in hydrostatic pressure differenceprovided by the low pressure tank may be up to about 45.9 Bar pressure,or about 450/gravitational factor or about 450/9.8. 5 ‘5’ may comprisedesalinated water transferred from the low pressure tank to a pump. Insome embodiments, the pressure of ‘5’ may be about equivalent to thepressure inside ‘4’. In some embodiments, the pressure of ‘5’ may belower than the pressure of ‘7’ at about the same elevation. 6 ‘6’ maycomprise a pump, or pressure exchanger, or other liquid transfer device.‘6’ may transfer desalinated water from a low pressure tank to anapplication requiring water, or a post treatment step, or water storage,or any combination thereof. In some embodiments, ‘6’ may pumpdesalinated water to the surface or to an elevation near, or at, orabove the elevation of a water body. ‘6’ may provide the additionalpower or pressure required to overcome the osmotic pressure of seawater,or power desalination, or enable desalination, or any combinationthereof. 7 ‘7’ may comprise freshwater or desalinated water transferredfrom a pump to a post treatment step. In some embodiments, ‘7’ maytransfer desalinated water from the elevation of the pump and/or lowpressure tank to an elevation at, or near, or above the elevation of awater body. In some embodiments, ‘7’ may transfer desalinated water froma low pressure tank to an application requiring water, or a posttreatment step, or water storage, or any combination thereof. In someembodiments, ‘7’ may comprise a riser or pipe. 8 ‘8’ may comprise astorage unit or storage facility or storage reservoir for desalinatedwater or freshwater. 9 ‘9’ may comprise desalinated water after a posttreatment step transferred to a storage unit or storage facility orstorage reservoir comprising desalinated water, or freshwater, or anycombination thereof. 10  ‘10’ may comprise a floating vessel housing aportion of the system or process. In the present embodiment, ‘10’ maycomprise a vessel with a post-treatment step, or a pump or powertransfer device, or a desalinated water storage unit or storage facilityor storage reservoir, or any combination thereof. ‘10’ may be moored.‘10’ may be attached to a detachable or disconnectable mooring system.In some embodiments, ‘10’ may produce hydrogen or other chemicals fromthe desalinated water. In some embodiments. ‘10’ may transfer thedesalinated water to a vessel or ship, or in a pipeline, or anycombination thereof to an application. 11 and ‘To ‘11’ may comprisedesalinated water, or freshwater, or chemicals derived from App’desalinated water, or any combination thereof transferred to anapplication. In some embodiments, ‘11’ may comprise a riser, or apipeline, or any combination thereof. RO ‘RO’ may comprise a reverseosmosis desalination system or process, or may comprise a reverseosmosis membrane module, or may comprise a membrane separation process,or may comprise a pressure difference driven desalination system orprocess, or any combination thereof. It may be desirable to locate ‘RO’at a lower elevation than the elevation of the seawater intake, or thehighest elevation point of the liquid column, or the highest elevationpoint of ‘3’ or the highest elevation point of ‘6’, or any combinationthereof to benefit from the energy efficiency and supplied powerbenefits of the natural hydrostatic pressure difference between a liquidcolumn comprising desalination feed and a liquid column comprisingdesalinated water or freshwater. In some embodiments, it may bedesirable to locate ‘RO’ at the lowest possible, or desirable, orpractical elevation. In some embodiments, ‘RO’ may be located on theseabed or seafloor. In some embodiments, ‘RO’ may be suspended ortethered or otherwise located above the seafloor. In some embodiments,it may be desirable for ‘RO’ to be located beneath the surface of a bodyof water or a body of liquid. Electricity ‘Electricity’ may comprise apower source. In some embodiments, ‘Electricity’ may comprise powersupplied from an external source, or may comprise power supplied from aninternal source, or may comprise power supplied from an offshore source,or may comprise power supplied by an onshore source, or may comprisepower supplied from the discharging of desalination retentate orconcentrate, or any combination thereof. Post ‘Post’ may comprise a posttreatment step. In some embodiments, ‘Post’ may comprise adding orremoving salts, or biocides, or minerals, or other potential chemicalsrequired for some applications. In some embodiments, ‘Post’ may comprisedesalination post-treatment systems and methods known in the art. Insome embodiments, desalinated water may bypass ‘Post’ or otherwise betransferred into ‘8’ if, for example, ‘Post’ is unnecessary orundesired. Ocean ‘Ocean’ may comprise a body of water, which, mayinclude, but is not limited to, an ocean, or sea, or bay, or estuary, orlake, or any combination thereof Seabed ‘Seabed’ may comprise theseafloor or land located at or near the bottom of a body of water orbody of liquid.

Example FIG. 118 Step-by-Step Description

(1) Seawater transferred into a desalination module, such as a reverseosmosis module at a lower elevation. In some embodiments, the depth ofthe reverse osmosis module, or the seawater intake, or both maydesirably be sufficiently deep for the hydrostatic pressure to begreater than the osmotic pressure of the seawater. For example, in someembodiments, the difference in pressure between the hydrostatic pressureof seawater at the water depth of the reverse osmosis module and thepressure of the permeate or desalinated water may comprise the drivingforce or a significant driving force for the flow of seawater into thereverse osmosis module and the desalination of the seawater ordesalination feed. In some embodiments, the elevation of the reverseosmosis module and/or the seawater intake may be significantly lowerthan the elevation of the pump or lower pressure tank to, for example,maximize or enhance the potential natural gravitational hydrostaticpressure difference between the desalinated water and the desalinationfeed or seawater. In some embodiments, pressure may be added using apump on the seawater feed or desalination feed or seawater intake or apump may be located on the seawater feed or desalination feed orseawater intake.

(2) Desalination feed, which may comprise seawater or pre-treatedseawater, may be transferred into a reverse osmosis desalination module.In the reverse osmosis module, the pressure of the desalination feed maybe greater on the desalination feed side than the desalination permeateside of the membrane. In the reverse osmosis module, wherein thedesalination feed may be separated into desalination permeate, which maycomprise desalinated water, and desalination concentrate or retentate,which may comprise a brine effluent. The desalination concentrate may bereleased or discharged. In some embodiments, the desalinationconcentrate may be released or discharged at an elevation near, or at,or lower than the elevation of the reverse osmosis module and/or powermay be generated from the gravitational hydrostatic pressure differencefrom the density difference between the seawater and the desalinationconcentrate in a liquid column. The permeate or the desalinated watermay be transferred to a higher elevation region.

(3) In the higher elevation region, the desalinated water may betransferred into a lower pressure tank. A lower pressure tank maycomprise a tank with an internal pressure lower than the gravitationalhydrostatic pressure at the depth or elevation or relative to the liquidcolumn gravitational hydrostatic head. At least a portion of desalinatedwater may be pumped out of the lower pressure tank, which may involve abatch, or semi-batch, or continuous process.

(4) Desalinated water may be pumped to an application, or to a storagevessel on or near the surface of the water body, or a subsea storagevessel, or a subsea pipeline or riser, or any combination thereof. Insome embodiment.

(5) The desalinated water may undergo post-treatment or furtherprocessing before transfer into storage, or to a storage vessel on ornear the surface of the water body, or a subsea storage vessel, or asubsea pipeline or riser, or any combination thereof.

FIG. 119

FIG. 119 may comprise the same embodiment as FIG. 118 , except mayemploy a subsea post treatment step and/or a subsea desalinated waterstorage facility, or storage unit, or storage vessel, or any combinationthereof.

FIG. 120

FIG. 120 may comprise a desalination process or system wherein reverseosmosis desalination occurs in a lower elevation region subsea and/orpost treatment is conducted subsea and/or desalinated water istransferred to an application, or to shore, or any combination thereof.

FIG. 121

FIG. 121 may comprise a desalination process or system whereinpre-treatment and reverse osmosis desalination may be conducted offshoreand/or post treatment and water storage and distribution may beconducted on land and/or a riser or pipeline transfers desalinated waterfrom the offshore portion of the desalination system or process to theonshore portion of the desalination system or process. In someembodiments, pre-treatment may comprise transferring deep seawaterintake or deep seawater feed to at or near the surface of a water bodyto depressurize and/or remove at least a portion of dissolved gases. Insome embodiments, the pump and/or other equipment or moving parts may belocated at or near the surface of the water body or in a higherelevation region relative to the reverse osmosis system. In someembodiments, the liquid column or elevation difference may comprise thedifference in elevation between the reverse osmosis module and theelevation of the on-land portions of the desalination process or systemand/or the difference in elevation between the pre-treatment and/or pumpand the reverse osmosis module.

FIG. 122

FIG. 122 may comprise an embodiment where the reverse osmosis module maybe located in a lower elevation region subsea and the desalinated wateris transferred to a higher elevation region, which may comprise a higherelevation region on land. The natural gravitational hydrostatic pressuredifference may be driven by the difference in the gravitationalhydrostatic pressure of the seawater at the depth of the seawater intakeor the reverse osmosis module and the gravitational hydrostatic pressureof desalinated water transferred to land or the higher elevation region.

FIG. 123 Summary

FIG. 123 may relate to a system or process for desalinating water,wherein at least a portion of power is generated from the discharging ofbrine, or desalination concentrate, or desalination retentate, or brineeffluent, or any combination thereof. In some embodiments, power may begenerated by forming a liquid column, wherein brine, which may begenerated from a desalination process, is transferred from a higherelevation region to a lower elevation region, which may be subsea,wherein the brine is discharged in the lower elevation region, and/orgenerating power from the difference in the gravitational hydrostaticpressure between the higher density brine and the lower densityseawater, or ocean water, or liquid in the body of water, or anycombination thereof at the same or similar depth or elevation. In someembodiments, power may be generated by discharging brine at a lowerelevation than the elevation which the brine was created or formed. Insome embodiments, brine may be transferred through a pipe, or riser, orany combination thereof, which may enable the formation of a liquidcolumn, which may facilitate the formation of the gravitationalhydrostatic pressure difference or the pressure difference. In someembodiments, power may be generated using a turbine, or electricgenerator, or a reversible pump/generator, or a pump, or a powerexchanger, or a power transfer device, or a power generation device, ora hydraulic power generator, or a pneumatic power transfer device, or ahydraulic power transfer device, or a power recovery device, or adesalination system or process, or any combination thereof. In someembodiments, power generated from the discharge of brine may betransferred to a desalination system or process, or transferred to anapplication, or transferred to an electricity grid, or transferred aselectricity, or transferred as hydraulic pressure, or transferred asmechanical energy, or transferred as kinetic energy, or transferred aselectromagnetic energy, or transferred as chemical energy, or anycombination thereof. In some embodiments, the desalination process orsystem, or brine generation process or system, or any combinationthereof may comprise, including, but not limited to, one or more or anycombination of the following: a desalination system or process known inthe art, or reverse osmosis, or nanofiltration, or mechanical vaporcompression distillation, or vacuum distillation, or distillation, ormultistage flash distillation, or membrane distillation, or forwardosmosis, or osmotically assisted reverse osmosis, or extractivedistillation, or cryodesalination, or electrodialysis, or a separationsystem or process.

The present embodiment may comprise a floating system or process, or asubsea system or process, or an on-land system or process, or onplatform system or process, or offshore system o process, or seabedbased system or process, or any combination thereof.

In some embodiments, power or energy may be stored by storing brine in astorage reservoir, or storage unit at an elevation higher than thesecond elevation or an elevation higher than the brine discharge outlet.

Example FIG. 123 Key

Example FIG. 123 Key Label Description 1 ‘1’ may comprise seawaterintake or desalination feed intake. In some embodiments, it may bedesirable far at least a portion of ‘1’ may be located at an elevationor in a location within a body of water with low turbidity, which mayminimize the required pre-treatment, if any. In some embodiments, ‘1’may be transferred to the surface or to a higher elevation region forpre-treatmem, or to remove at least a portion of dissolved gases, or anycombination thereof, and then transferred to the reverse osmosis step ortohter desalination step. 2 ‘2’ may comprise desalination feed afterpre-treatment and/or before pressurization with a pump or pressureexchanger or power transfer device. 3 ‘3’ may comprise a pump, orpressure exchanger, or power transfer device, or any combinationthereof. ‘3’ may pressurize or apply pressure to the desalination feedand/or transfer the desalination feed into a pipe or transfer totransfer the desalination feed to a reverse osmosis step, or pressuredriven desalination step, or any combination thereof. 4 ‘4’ may comprisepressurized desalination feed transferred from a pump to a desalinationsystem or process, such as a reverse osmosis system or process. 5 ‘5’may comprise concentrate or retentate or brine effluent or brine.Concentrate or retentate or brine effluent may be transferred from ahigher elevation region to a lower elevation region. For example,concentrate or retentate or brine effluent may be transferred from thesource of the concentrate or retentate or brine effluent, which maycomprise a desalination process, to a lower elevation region, which maybe located subsea. Concentrate or retentate or brine effluent may betransferred from the higher elevation region to the lower elevationregion using a pipe, or pipeline, or a riser. A liquid column may becreated wherein the gravitational hydrostatic pressure in ‘5’ is greaterthan the gravitational hydrostatic pressure in the ocean or sea or bodyof water at the same water depth or same elevation, and/or wherein thedeeper the depth or lower the elevation, the gravitational hydrostaticpressure in ‘5’ may be greater than the gravitational hydrostaticpressure in the ocean or sea or body of water as the same elevation. 6‘6’ may comprise a generator, or turbine, or pressure exchanger, orpower exchanger, or power generation device, or power transfer device,or power recovery device, or any combination thereof. ‘6’ may be locatedat a lower elevation region. Concentrate or retentate or brine effluentmay be transferred into ‘6’, wherein ‘6’ may generate power from thepressure difference or gravitational hydrostatic pressure differencebetween the concentrate or retentate or brine effluent and the adjacentbody of water. Power generated from may be transferred to a desalinationsystem or process, or to an application, or may be converted, or may bestored, or any combination thereof. 7 ‘7’ may comprise dischargedconcentrate or retentate or brine effluent, which may comprisedischarging or releasing into a body of water, which may comprise a seaor ocean, at a lower elevation than the source of the concentrate orretentate or brine effluent. ‘7’ may comprise a brine discharge outlet.‘7’ may be at a lower pressure than ‘5’ at the same elevation. ‘7’ maycomprise diffusers or distributors, which may minimize or reduce thepotential for a localized increase in salinity near or adjacent to thedischarge. 8 ‘8’ may comprise desalination permeate or desalinatedwater. Desalinated water (pipe) may be transferred to a post treatmentstep, or to desalinated water storage or freshwater storage, or anycombination, thereof. 8 ‘8’ may comprise a storage unit, or storagereservoir, or storage vessel, or storage (storage) facility, or anycombination thereof comprising desalinated water or freshwater. 9 ‘9’may comprise desalinated water transferred to a storage unit, or to anapplication, or any combination thereof. Desalinated water or freshwatermay be transferred in a pipe, or pipeline or riser to an application, orfurther treatment step, or any combination thereof. 10  ‘10’ maycomprise a floating vessel, housing a portion of the system or process.‘10’ may be moored. ‘10’ may be attached to a detachable ordisconnectable mooring system. In some embodiments, ‘10’ may producehydrogen, or other chemicals from the desalinated water. In someembodiments, ‘10’ may transfer the desalinated water to a vessel orship, or in a pipeline, or any combination thereof to an application.E-1 ‘E-1’ may comprise a power source. ‘E-1’ may comprise power sourcedfrom an external source, or an internal source, or any combinationthereof, which may be employed to power desalination, or other systemsor processes, or any combination thereof. E-2 ‘E-2’ may comprise powergenerated from the discharge of brine. ‘E-2’ may be transferred toprovide at least a portion of the power for desalination, or to a powerapplication, or any combination thereof. Pre ‘Pre’ may comprise apre-treatment step. ‘Pre’ may comprise removing dissolved gases from theseawater intake or desalination feed. ‘Pre’ may comprise addingadditives, or filtration, or coagulation, or separation, or othertreatment, or desalination pre-treatments known in the art, or anycombination thereof. It may be advantageous to locate ‘Pre’ in anaccessible location or on a floating vessel to enable maintenance and/orto reduce energy consumption associated with depressurization and/orremoval of dissolved gases. RO ‘RO’ may comprise a reverse osmosisdesalination system or process, or may comprise a reverse osmosismembrane module, or may comprise a membrane separation process, or maycomprise a pressure difference driven desalination system or process, orany combination thereof. RO may comprise a desalination system orprocess, which may include, but is not limited to, desalination systemsor processes described herein, or desalination systems or processesdescribed in the art, or any combination thereof. Post ‘Post’ maycomprise a post treatment step. In some embodiments, ‘Post’ way compriseadding or removing salts, or biocides, or minerals, or other potentialchemicals required for some applications. In some embodiments, ‘Post’may comprise desalination post-treatment systems and methods known inthe art. In some embodiments, desalinated water may bypass ‘Post’ orotherwise be transferred to a storage reservoir or an application if,for example, ‘Post’ is unnecessary or undesired. Ocean ‘Ocean’ maycomprise a body of water, which may include, but is not limited to, anocean, or sea, or bay, or estuary, or lake, or any combination thereof.Seabed ‘Seabed’ may comprise the seafloor or land located at or near thebottom of a body of water or body of liquid.

Example FIG. 123 Step-by-Step Description

(1) Seawater or other desalination intake or desalination feed may betransferred to a pre-treatment step. Seawater or other desalinationintake or desalination feed may be sourced from a body of water. In someembodiments, it may be desirable for the seawater intake opening to belocated in a region or depth of a water body wherein the seawaterpossesses low turbidity to, for example, minimize or reduce potentialfouling or scaling or pre-treatment costs.

(2) Seawater or other desalination intake or desalination feed may bepre-treated. In some embodiments, pre-treatment may comprise removing atleast a portion of dissolved gases. In some embodiments, pre-treatmentmay comprise the addition or removal of chemicals, and/or the filtrationof particulates.

(3) Desalination feed, which may comprise seawater or treated seawater,may be pumped into a desalination system or process. In someembodiments, desalination feed may be pumped and/or pressurized andtransferred into a reverse osmosis desalination system or process. Insome embodiments, desalination feed may be at least partiallydesalinated or converted into freshwater or desalinated water using asystem or process in addition to, or other than, reverse osmosisdesalination. In some embodiments, the seawater, or brine effluent, orany combination thereof may be evaporated to form brine or high densitybrine to facilitate power generation in later steps.

(4) In some embodiments, a system or process may produce brine with adensity greater than the density of seawater or the water in the body ofwater. In some embodiments, a system or process may produce desalinatedwater and concentrate, or retentate, or brine effluent. Desalinatedwater may be transferred to a post-treatment step, or a storage unit, oran application, or a chemical synthesis process, or a hydrogenproduction process, or a chemical process, or a pipeline, or a riser, orany combination thereof.

(5) Brine may be transferred from a higher elevation region or from abrine source in a higher elevation region, to a lower elevation region,where the brine may be discharged or released to generate power. Powermay be generated from the gravitational hydrostatic pressure differencedue to the elevation difference between the higher elevation region andlower elevation region and the difference in density between the brineand the adjacent seawater or body of water at about the same elevation.Generated power may be transferred to a desalination system or process,or an application, or any combination thereof. For example, generatedpower may be transferred to a desalination system or process, or anapplication, or any combination thereof using an electricitytransmission cable, or electricity transmission infrastructure, orenergy storage, or a power transfer mechanism, or any combinationthereof.

Example Exemplary Embodiments

Density Differential Desalination Example Exemplary Embodiments

(1a) A system for desalinating water comprising:

A first liquid column;

A second liquid column;

Wherein the first liquid column comprises desalination feed;

Wherein the second liquid column comprises desalinated water; and

Wherein at least a portion of the power for desalination is provided bythe difference in gravitational hydrostatic pressure between the firstliquid column and the second liquid column due to the density differencebetween the desalination feed and desalinated water

(1a) A system for desalinating water comprising:

A first liquid column;

A second liquid column;

Wherein the first liquid column comprises desalination feed;

Wherein the second liquid column comprises desalinated water; and

Wherein at least a portion of the pressure for desalination is providedby the difference in gravitational hydrostatic pressure between thefirst liquid column and the second liquid column due to the densitydifference between the desalination feed and desalinated water

(2) The system of example exemplary embodiment 1 wherein saiddesalination feed comprises seawater

(3) The system of example exemplary embodiment 1 wherein saiddesalinated water comprises freshwater

(4) The system of example exemplary embodiment 1 wherein the system isin a body of water

(5) The system of example exemplary embodiment 4 wherein the body ofwater comprises an ocean, or a sea

(6) The system of example exemplary embodiment 4 wherein the systemcomprises a first elevation and a second elevation; and wherein thefirst elevation comprises the elevation of the surface of a body ofwater; and wherein the second elevation comprises an elevation lowerthan the first elevation

(7) The system of example exemplary embodiment 6 wherein a reverseosmosis desalination membrane is positioned at the second elevation

(8) The system of example exemplary embodiment 1 wherein the firstcolumn comprises a body of water

(9) The system of example exemplary embodiment 7 wherein the firstcolumn comprises a pipe transferring desalination feed between the firstelevation and the reverse osmosis desalination membrane at the secondelevation

(10) The system of example exemplary embodiment 7 wherein the secondcolumn comprises a pipe transferring desalinated water between thereverse osmosis desalination membrane at the second elevation and anapplication at the first elevation

(1) The system of example exemplary embodiment 10 wherein said pipecomprises a riser

(12) The system of example exemplary embodiment 6 wherein the secondelevation is at an elevation greater than 1,000 meters lower than theelevation of the first elevation

(13) The system of example exemplary embodiment 7 wherein desalinationconcentrate is discharged from the reverse osmosis at an elevationwithin 50 meters of the elevation of the reverse osmosis membrane

(14) The system of example exemplary embodiment 7 wherein thedesalination concentrate is discharged from the reverse osmosis at anelevation equal to or lower than the elevation of the reverse osmosismembrane

(15) The system of example exemplary embodiment 1 wherein desalinationfeed is pre-treated before transfer into the liquid column

(16) The system of example exemplary embodiment 15 wherein saidpretreatment is located at the first elevation; and wherein saidpretreatment comprises removing at least a portion of dissolved gases

(17) The system of example exemplary embodiment 9 wherein additionalpressure is applied to the desalination feed in the first liquid columnusing a pump at the first elevation

(18) The system of example exemplary embodiment 9 wherein additionalpressure is applied to the desalination feed in the first liquid columnusing a pressure exchange with a discharging fluid displacement energystorage system

(19) The system of example exemplary embodiment 9 wherein additionalpressure is applied to the desalination feed in the first liquid columnusing a pump at an elevation between the first elevation and the secondelevation

(20) The system of example exemplary embodiment 9 wherein additionalpressure is applied to the desalination feed in the first liquid columnusing a pump at the second elevation

(21) The system of example exemplary embodiment 1 wherein the differencein gravitational hydrostatic pressure between the first liquid column atthe second liquid column at the second elevation is greater than 5 Bar

(22) The system of example exemplary embodiment 1 wherein the differencein pressure between the first liquid column and the second liquid columnis supplemented by reducing the pressure of the second liquid column

(23) The system of example exemplary embodiment 22 wherein the pressureof the second liquid column is reduced by transferring desalinated waterin the second liquid column into a lower pressure tank

(24) The system of example exemplary embodiment 23 wherein the internalpressure of the lower pressure tank is lower than the gravitationalhydrostatic pressure associated with the elevation difference betweenthe elevation of the lower pressure tank and the surface of the body ofwater

(25) The system of example exemplary embodiment 23 wherein the internalpressure of the lower pressure tank is lower than the gravitationalhydrostatic pressure associated with the elevation difference betweenthe elevation of the lower pressure tank and the outlet of the secondliquid column

(26) The system of example exemplary embodiment 23 wherein the elevationof the lower pressure tank is between the first elevation and the secondelevation

(27) The system of example exemplary embodiment 23 wherein the elevationof the lower pressure tank is lower than the first elevation by anelevation difference about equal to or greater than the hydrostatic headpressure for desalinating desalination feed at a desired recovery ratiominus the gravitational hydrostatic pressure difference between thefirst liquid column and the second liquid column

(28) The system of example exemplary embodiment 23 wherein the pressureof the lower pressure tank is maintained by a pump transferringdesalinated water from the lower pressure tank

(29) The system of example exemplary embodiment 23 wherein the pressureof the lower pressure tank is maintained by a pressure exchangertransferring desalinated water from the lower pressure tank powered bypressure exchanging with a discharging fluid displacement energy storagesystem

(30) The system of example exemplary embodiment 1 wherein the densitydifference between desalination feed and the desalinated water isgreater than 0.005 kg/L

Brine Power Generation Example Exemplary Embodiments

A system for generating power comprising:

A brine source;

A pipe;

A generator;

A body of water; and

A brine discharge outlet

Wherein the brine source is at a first elevation and the brine dischargeoutlet is at a second elevation; and

Wherein the first elevation is higher than the second elevation; and

Wherein the pipe connects the brine source at the first elevation to thebrine discharge outlet at the second elevation; and

Wherein the brine discharge outlet and at least a portion of the pipeare located beneath the surface of the body of water; and

Wherein power is generated by transferring brine from the firstelevation to the second elevation

The system of example exemplary embodiment 1 wherein power is generateddue to the gravitational hydrostatic pressure difference between thebrine in the pipe and the adjacent body of water due to the densitydifference between brine and seawater

The system of example exemplary embodiment 1 wherein a generator isconnected to the pipe located between the brine source at the firstelevation and discharge outlet at the second elevation

The system of example exemplary embodiment 1 wherein the body of watercomprises a sea or ocean

The system of example exemplary embodiment 1 wherein the brine comprisesdesalination concentrate, or desalination retentate

The system of example exemplary embodiment 1 wherein the brine sourcecomprises a desalination system

The system of example exemplary embodiment 1 wherein the pipe comprisesa riser

The system of example exemplary embodiment 1 wherein the brine isdischarged into the body of water through the brine discharge outlet atthe second elevation

The system of example exemplary embodiment 1 wherein brine enters thepipe at the first elevation

The system of example exemplary embodiment 1 wherein the generator islocated beneath the surface of a water body at the second elevation

The system of example exemplary embodiment 6 wherein the generatorgenerates power in the form of electricity; and wherein the generatedelectricity is transferred to provide at least a portion of power to thedesalination system

The system of example exemplary embodiment 6 wherein at least a portionof the desalination system is floating on the body of water

The system of example exemplary embodiment 6 wherein at least a portionof the desalination system is beneath the surface of a body of water atthe first elevation

The system of example exemplary embodiment 6 wherein at least a portionof the desalination system is on land at the first elevation

The system of example exemplary embodiment 1 wherein the brine sourcecomprises an evaporation process

The system of example exemplary embodiment 1 wherein the generatorcomprises a power exchanger, wherein at least a portion of the powergenerated is employed to pressurize at least a portion of desalinationfeed

The system of example exemplary embodiment 1 wherein the dischargeoutlet comprises distributors to reduce the localized increase insalinity adjacent to the discharge

The system of example exemplary embodiment 1 wherein the dischargeoutlet is at an elevation greater than 1000 meters below the elevationof the surface of the water body

The system of example exemplary embodiment 1 wherein the difference inelevation between the first elevation and second elevation is greaterthan 1000 meters

The system of example exemplary embodiment 1 wherein the generator is atan elevation within 50 meters of the discharge outlet

The system of example exemplary embodiment 6 wherein the power sourcefor desalination comprises electricity transferred from an externalsource through a subsea cable

The system of example exemplary embodiment 11 wherein power transferredfrom the generator to the desalination system is transferred employingthe same subsea umbilical

The system of example exemplary embodiment 2 wherein the densitydifference between the brine and the seawater is greater than 0.005 kg/L

The system of example exemplary embodiment 1 wherein energy is stored bystoring brine in a storage reservoir at the first elevation

Notes

Note: In some embodiments, power may be transferred employing a subseaumbilical and/or a subsea cable.

Note: In some embodiments, the density difference between brine orconcentrate or retentate and seawater or desalination feed may begreater than or equal to, including, but not limited to, one, or more,or any combination of the following: 0.0001 kg/L, or 0.001 kg/L, or0.002 kg/L, or 0.003 kg/L, or 0.004 kg/L, or 0.005 kg/L, or 0.006 kg/L,or 0.007 kg/L, or 0.008 kg/L, or 0.009 kg/L, or 0.010 kg/L, or 0.011kg/L, or 0.012 kg/L, or 0.013 kg/L, or 0.014 kg/L, or 0.015 kg/L, or0.016 kg/L, or 0.017 kg/L, or 0.018 kg/L, or 0.019 kg/L, or 0.020 kg/L,or 0.021 kg/L, or 0.022 kg/L, or 0.023 kg/L, or 0.024 kg/L, or 0.025kg/L, or 0.026 kg/L, or 0.027 kg/L, or 0.028 kg/L, or 0.029 kg/L, or0.030 kg/L, or 0,035 kg/L, or 0.040 kg/L, or 0.045 kg/L, or 0.050 kg/L.

Note: In some embodiments, the density difference between seawater ordesalination feed and desalinated water or desalination permeate orfreshwater may be greater than or equal to, including, but not limitedto, one, or more, or any combination of the following: 0.0001 kg/L, or0.001 kg/L, or 0.002 kg/L, or 0.003 kg/L, or 0.004 kg/L, or 0.005 kg/L,or 0.006 kg/L, or 0.007 kg/L, or 0.008 kg/L, or 0.009 kg/L, or 0.010kg/L, or 0.011 kg/L, or 0.012 kg/L, or 0.013 kg/L, or 0.014 kg/L, or0.015 kg/L, or 0.016 kg/L, or 0.017 kg/L, or 0.018 kg/L, or 0.019 kg/L,or 0.020 kg/L, or 0.021 kg/L, or 0.022 kg/L, or 0.023 kg/L, or 0.024kg/L, or 0.025 kg/L, or 0.026 kg/L, or 0.027 kg/L, or 0.028 kg/L, or0.029 kg/L, or 0.030 kg/L, or 0.035 kg/L, or 0.040 kg/L, or 0.045 kg/L,or 0.050 kg/L.

Note: The gravitational hydrostatic pressure difference between thedesalination feed in the first liquid column and desalinated water inthe second liquid column at the second elevation may be greater than orequal to, including, but not limited to, one, or more, or anycombination of the following: 0.01 Bar, or 0.5 Bar, or 1.0 Bar, or 1.5Bar, or 2 Bar, or 2.5 Bar, or 3 Bar, or 3.5 Bar, or 4.0 Bar, or 4.5 Bar,or 5.0 Bar, or 5.5 Bar, or 6.0 Bar, or 6.5 Bar, or 7.0 Bar, or 7.5 Bar,or 8.0 Bar, or 8.5 Bar, or 9.0 Bar, or 9.5 Bar, or 10 Bar, or 11 Bar, or12 Bar, or 13 Bar, or 14 Bar, or 15 Bar, or 16 Bar, or 17 Bar, or 18Bar, or 19 Bar, or 20 Bar, or 21 Bar, or 22 Bar, or 23 Bar, or 24 Bar,or 25 Bar, or 26 Bar, or 27 Bar, or 28 Bar, or 29 Bar, or 30 Bar, or 35Bar, or 40 Bar, or 45 Bar, or 50 Bar.

Note: The gravitational hydrostatic pressure difference between seawaterand brine in a pipe at the second elevation may be greater than or equalto, including, but not limited to, one, or more, or any combination ofthe following: 0.01 Bar, or 0.5 Bar, or 1.0 Bar, or 1.5 Bar, or 2 Bar,or 2.5 Bar, or 3 Bar, or 3.5 Bar, or 4.0 Bar, or 4.5 Bar, or 5.0 Bar, or5.5 Bar, or 6.0 Bar, or 6.5 Bar, or 7.0 Bar, or 7.5 Bar, or 8.0 Bar, or8.5 Bar, or 9.0 Bar, or 9.5 Bar, or 10 Bar, or 11 Bar, or 12 Bar, or 13Bar, or 14 Bar, or 15 Bar, or 16 Bar, or 17 Bar, or 18 Bar, or 19 Bar,or 20 Bar, or 21 Bar, or 22 Bar, or 23 Bar, or 24 Bar, or 25 Bar, or 26Bar, or 27 Bar, or 28 Bar, or 29 Bar, or 30 Bar, or 35 Bar, or 40 Bar,or 45 Bar, or 50 Bar.

Note: In some embodiments, seawater intake, or desalination feed, or anycombination thereof may be transferred from deep water to the surface ofa water body, to, for example, depressurize the seawater intake, ordesalination feed, or any combination thereof which may result in therelease of at least a portion of dissolved gases from the seawaterintake, or desalination feed, or any combination thereof. Transferringdeep seawater or other desalination feed to a higher elevation or alower pressure environment may be a pre-treatment step to remove atleast a portion of dissolved gases. In some embodiments, thedesalination feed may be mixed, or agitated, or sparged with air, orsparged with gas, or any combination thereof to accelerate the ratewhich dissolved gases are released from the desalination feed. It may bedesirable to remove at least a portion of dissolved gases to, forexample, prevent or minimize the formation of gas or supercritical fluidduring the desalination step or reverse osmosis step of a desalinationsystem or process.

Note: in some embodiments, dissolved gases in seawater may comprisecarbon dioxide and/or said carbon dioxide may be captured and/orconverted and/or utilized. In some embodiments, the released dissolvedgases may comprise a similar composition to air, or may comprise airgases, or any combination thereof. In some embodiments, releaseddissolved gases may be vented into the air.

Note: Some embodiments may comprise a floating offshore desalinationsystem wherein the desalination concentrate or retentate, which maycomprise brine effluent, may be transferred through a riser pipe intodeep water. At or near the bottom of the riser pipe may be a turbine orgenerator which may generate power or electricity from the hydrostaticpressure difference in the liquid column between the adjacent seawateror body of water and the higher density desalination brine effluent.Electricity or power may be transferred to the desalination process tofacilitate or power at least a portion of desalination, or electricityor power may be transferred to another application, or electricity orpower may be transferred to power another desalination system, or anycombination thereof. For example, the generator or turbine may comprisea pressure exchanger, which may pressure exchange with desalination feedand facilitate or at least partially power desalination at a lowerelevation. Some embodiments be land based if, for example, land may berelatively close to ultra-deep water. For example, if the water is 3,000meters deep, the potential power generated may be 10-20% of theelectricity consumed in a reverse osmosis desalination process.

Note: Some embodiments may create a pressure difference sufficient fordesalination by reducing the pressure of the desalinated water liquidcolumn or the permeate liquid column or freshwater liquid column to apressure below the gravitational hydrostatic pressure of the liquidcolumn. For example, some embodiments may involve a pump-out tank or alower pressure tank, wherein a desalinated water liquid columncomprising a riser or pipeline is connected to a tank with an internalpressure lower than the hydrostatic pressure at the water depth, whereinsaid the lower internal pressure is maintained by a pump which pumpswater from the tank into a pipeline or riser to a post treatment step,or an application, or any combination thereof. In some embodiments, thepump-out tank or lower pressure tank may be located beneath the surfaceof a body of water and/or at a water depth or elevation associated withthe necessary reduction in hydrostatic head or liquid columngravitational pressure to enable or facilitate or drive desalination. Itmay be desirable for said pump and/or pump-out tank and/or lowerpressure tank to be located at a water depth which is shallower or moreaccessible and/or the minimum desired water depth to sufficiently reducehydrostatic pressure of the desalinated water liquid column fordesalination. For example, if the total liquid column traverses anelevation of 3,000 meters or has a vertical elevation of 3,000 meters,the natural hydrostatic pressure difference between the liquid columnsmay be 7.65 Bar, which may mean the lower pressure tank or thedesalinated water liquid column must be at a pressure 19.35 Bar lowerthan the natural hydrostatic pressure to overcome the osmotic pressureof seawater or at a pressure 62.35 Bar lower than the naturalhydrostatic pressure to provide the same applied pressure differenceemployed in an example reverse osmosis system with a 40% recovery ratio,which means it may be desirable for the water depth of the lowerpressure tank and/or the pump may be at least 199.43 meters, or at least620.8 meters, respectively if the lower pressure tank has an internalpressure of about 1 Bar.

Note: A liquid column may comprise a liquid body traversing or spanninga significant elevation. In some embodiments, a liquid column maycomprise a pipe or riser containing liquid. In some embodiments, aliquid column may comprise an open body of water. For example, a liquidcolumn may comprise a liquid body traversing or spanning an elevationdifference of greater than 10 meters, or 20 meters, or 30 meters, or 40meters, or 50 meters, or 60 meters, or 70 meters, or 80 meters, or 90meters, or 100 meters, or 150 meters, or 200 meters, or 250 meters, or300 meters, or 350 meters, or 400 meters, or 450 meters, or 500 meters,or 600 meters, or 700 meters, or 800 meters, or 900 meters, or 1,000meters, or 1,250 meters, or 1,500 meters, or 1,750 meters, or 2,000meters, or 2,250 meters, or 2,500 meters, or 2,750 meters, or 3,000meters, or 3,250 meters, or 3,500 meters, or 4,000 meters, or 5,000meters, or 6,000 meters, or 7,000 meters, or 8,000 meters, or 9,000meters, or 10,000 meters, or 11,000 meters.

Note: Reverse osmosis desalination recovery percentage may be greaterthan or equal to one or more or any combination of the following: 0.1%,or 1%, or 5%, or 10%, or 15%, or 20%, or 25%, or 30%, or 35%, or 40%, or45%, or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or90%, or 95%

Note: In some embodiments, traversed elevation, or elevation difference,or vertical elevation may have the same meaning.

Note: In some embodiments, the reverse osmosis system or otherdesalination step may be suspended, or tethered above the seafloor.

Note: Some embodiments may be advantageous due to locating at least aportion of significant moving parts or parts requiring maintenance aboveor outside of the ocean or other water body. Some embodiments may beadvantageous due to locating at least a portion of significant movingparts or parts requiring maintenance at potentially accessible or easilyaccessible water depths or elevations, which in some embodiments mayinclude, but is not limited to, water depths of less than 1,000 meters.

Note: In some embodiments, pumps may comprise pressure exchangers, whichmay involve pressure exchanging with an energy storage system or fluidsin an energy storage system to power at least a portion of desalination.

Storing and Generating Power Embodiments without Generator

1. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump;

wherein the pump and the first and the second reservoir are operativelyconnected such that power is stored by displacing the second fluid inthe second storage reservoir by pumping the first fluid from the firststorage reservoir to the second storage reservoir and such that power isgenerated by allowing the pumped first fluid in the second storagereservoir to exit the second reservoir; and wherein the first fluid is aliquid.

2. The system of embodiment 1 wherein the system is configured togenerate power by transferring the first fluid into a power recoverydevice.

3. The system of embodiment 2 wherein said power recovery devicecomprises a pressure exchanger.

4. The system of embodiment 2 wherein said power recovery device isconfigured to transfer the power from the first fluid to a desalinationfeed stream.

5. The system of embodiment 2 wherein said power recovery device isconfigured to extract power from the first fluid to pressurize adesalination feed comprising water.

6. The system of embodiment 5 wherein said desalination feed comprisingwater comprises seawater or treated seawater.

7. The system of embodiment 5 wherein the system is configured such thatsaid pressurized desalination feed comprising water is transferred intoa reverse osmosis desalination system.

8. The system of embodiment 2 wherein the system is configured such thatthe first fluid is transferred into the first storage reservoir aftersaid power recovery.

9. The system of embodiment 1 wherein the first fluid comprises ahydrocarbon, butane, propane, LPG, water, ammonia, ethanol, methanol,kerosene, or any mixture thereof.

10. The system of embodiment 1 wherein the system is configured suchthat power in the first fluid is employed to generate electricity forpressurizing a desalination feed water.

11. The system of embodiment 10 wherein the system is configured suchthat the proportion of power converted into electricity relative to theproportion of power transferred to pressurize the desalination feedwater is adjustable.

12. The system of embodiment 5 wherein the system is configured suchthat the first fluid transferred into a power recovery device comprisesa pressure greater than an osmotic pressure of the desalination feedcomprising water.

13. The system of embodiment 1 wherein the first fluid comprises adesalination feed comprising water.

14. The system of embodiment 13 wherein the system is configured suchthat power is generated by transferring the low density fluid into adesalination system.

15. The system of embodiment 14 wherein the system is configured suchthat the first fluid transferred to a desalination system comprises apressure greater than the osmotic pressure of the desalination feedcomprising water.

16. The system of embodiment 13 wherein the system is configured suchthat at least a portion of the power in the first fluid is recoveredusing a power recovery device before transferring the first fluid to adesalination system.

17. The system of embodiment 13 wherein the system is configured suchthat at least a first portion of the first fluid is transferred to anelectric generator and at least a second portion of the first fluid istransferred to a desalination system,

wherein the electric generator generates electricity from at least aportion of the generated power in the first fluid, and

wherein the desalination system converts at least a portion of thegenerated power in the first fluid into desalinated water.

18. The system of embodiment 17 wherein the system is configured suchthat the proportion of first fluid transferred to the desalinationsystem and the proportion of first fluid transferred to the electricgenerator is adjustable.

19. The system of embodiment 17 wherein the system is configured suchthat the proportion of power in the first fluid transferred to thedesalination system and the proportion of power in the first fluidtransferred to the electric generator is adjustable.

20. The system of embodiment 13 wherein the system is configured suchthat the first fluid exiting the second storage reservoir is transferredinto a desalination system to produce desalinated water.

21. The system of embodiment 20 wherein desalination feed comprisingwater is added to the first storage reservoir to make up for theproduced desalinated water.

22. The system of embodiment 13 the system is configured such that thefirst fluid exiting the second storage reservoir is transferred into adesalination system to separate the first fluid into a desalinated waterpermeate and a desalination retentate using a semipermeable membrane.

23. The system of embodiment 1 wherein the low density fluid comprisesdesalinated water.

24. The system of embodiment 1 wherein the system is configured suchthat the stored power is employed to desalinate water.

25. The system of embodiment 24 wherein the system is configured suchthat the desalinated water is converted into chemicals selected from thegroup consisting of hydrogen, oxygen, synthetic fuels, fuels, ammonia,hydrogen derived chemicals, carbon dioxide derived chemicals, airderived chemicals, and any mixture thereof.

26. The system of embodiment 1 wherein the system is configured suchthat the higher elevation reservoir is locatable on land, floating onwater, or underwater.

27. The system of embodiment 24 wherein the system is configured suchthat the desalinated water is transportable by a pipeline, a riser, aship, an aircraft, a train, a truck, or a conveyor belt.

28. The system of embodiment 1 wherein the pump is configured topressurize a desalination feed comprising water.

29. A process for storing power and desalinating water comprising:

storing a first fluid in a first storage reservoir;

storing a second fluid which has a higher density than the first fluidin a second storage reservoir located at a lower elevation than thefirst storage reservoir;

operatively connecting a pump and the first and second reservoir suchthat power is stored by displacing the second fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir; and

allowing the first fluid to exit the second storage reservoir andpressure exchange with a desalination feed comprising water to generatepower.

30. A process for storing power and desalinating water comprising:

storing a first fluid in a first storage reservoir;

storing a second fluid which has a higher density than the first fluidin a second storage reservoir located at a lower elevation than thefirst storage reservoir;

operatively connecting a pump and the first and second reservoir suchthat power is stored by displacing the second fluid in the secondstorage reservoir by pumping the first fluid in the first storagereservoir to the second storage reservoir; and

allowing the first fluid to exit the second storage reservoir and entera desalination system;

wherein the first fluid comprises a desalination feed comprising water.

Storing and Generating Power Embodiments with Generator

1. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump; and

a generator;

wherein the pump, the generator, and the first and the second reservoirare operatively connected such that power is stored by displacing thesecond fluid in the second storage reservoir by pumping the first fluidin the first storage reservoir to the second storage reservoir and poweris generated or discharged by allowing the first fluid in the secondstorage reservoir to return to the first storage reservoir; and

wherein the first fluid is a liquid.

2. The system of embodiment 1 wherein the high density fluid is solublein the low density fluid.

3. The system of embodiment 1 wherein the second storage reservoircomprises at least one storage unit within it and wherein the system isconfigured such that the low density fluid and the high density fluidare storable within the same storage unit in the second storagereservoir.

4. The system of embodiment 3 wherein the system is configured such thatthe low density fluid is located above the high density fluid within thestorage unit.

5. The system of embodiment 3 wherein the system is configured such thata fluid-fluid interface separates the low density fluid from the highdensity fluid in the storage unit.

6. The system of embodiment 3 wherein the system is configured such thata chemocline or chemocline layer separates the low density fluid fromthe high density fluid.

7. The system of embodiment 3 wherein the system is configured such thata physical divider separates the low density fluid from the high densityfluid.

8. The system of embodiment 7 wherein the system is configured such thatthe physical divider occupies at least 50% of the cross sectional areaotherwise occupied by a fluid-fluid interface in the absence of thephysical divider.

9. The system of embodiment 7 wherein the system is configured such thatan elevation of the physical divider adjusts to follow a change inelevation of the fluid-fluid interface that would be present in theabsence of the physical divider.

10. The system of embodiment 7 wherein the system is configured suchthat the physical divider is floating.

11. The system of embodiment 7 wherein the system is configured suchthat the density of the physical divider is greater than the density ofthe low density fluid and less than the density of the high densityfluid.

12. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises at least one first reservoirstorage unit within it and the second storage reservoir comprises atleast one second reservoir storage unit within it and wherein the systemis configured such that the high density fluid and low density fluid arestored in the same storage units within the first storage reservoir andthe second storage reservoir.

13. The system of embodiment 2 wherein the system is configured suchthat at least a portion of high density fluid mixes with at least aportion of low density fluid.

14. The system of embodiment 13 wherein the system is configured suchthat at least a portion of high density fluid is removed from the lowdensity fluid by separation.

15. The system of embodiment 14 wherein the system is configured suchthat said separation comprises reverse osmosis, or forward osmosis, ordistillation, or evaporation, or electrodialysis, or gravitationalseparation, or decanting, or coalescing, or centrifuge, or filtration,or cryodesalination, or freeze desalination, solventing out, orprecipitation, or extraction, or extractive distillation.

16. The system of embodiment 2 wherein the system is configured suchthat at least a portion of low density fluid mixes with at least aportion of high density fluid.

17. The system of embodiment 16 wherein the system is configured suchthat at least a portion of low density fluid is removed from the highdensity fluid by separation.

18. The system of embodiment 17 wherein said separation comprisesreverse osmosis, or forward osmosis, or distillation, or evaporation, orgravitational separation, or decanting, or coalescing, or centrifuge, orfiltration, or cryodesalination, or freeze desalination, solventing out,or precipitation, or extraction, or extractive distillation.

19. The system of embodiment 2 wherein the low density fluid compriseswater and the high density fluid comprises brine.

20. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises a first and a second storageunit and wherein the system is configured such that the high densityfluid is stored within the first storage unit and the low density fluidis stored in the second storage unit.

21. The system of embodiment 20 wherein the high density fluid comprisesa liquid.

22. The system of embodiment 21 wherein the system is configured suchthat the first and the second storage unit are operably connected suchthat a gas is transferrable between the first and the second storageunit as liquid enters a unit and displaces the gas.

23. The system of embodiment 22 wherein the system is configured suchthat a semi-permeable barrier allows the transfer of gas whilepreventing the transfer of liquid.

24. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir is located under a body of water.

25. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir is at an elevation greater than thesurface of the body of water.

26. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises a floating structure.

27. The system of embodiment 1 further comprising a pressure exchanger.

28. The system of embodiment 27 wherein the system is configured suchthat the pressure exchanger is located at an elevation less than theelevation of the first storage reservoir and greater than or equal tothe elevation of the second storage reservoir.

29. The system of embodiment 1 wherein the low density fluid or highdensity fluid comprises desalinated water.

30. The system of embodiment 1 wherein the low density fluid or highdensity fluid comprises treated seawater.

Desalinating Water Embodiments

1. A system for desalinating water comprising:

a first liquid column operably connected to a second liquid column;

wherein the first liquid column comprises a desalination feed;

wherein the second liquid column comprises desalinated water; and

wherein the system is configured such that at least a portion ofpressure for desalination is provided by a difference in gravitationalhydrostatic pressure between the first liquid column and the secondliquid column due to a density difference between the desalination feedand the desalinated water.

2. The system of embodiment 1 wherein said desalination feed comprisesseawater.

3. The system of embodiment 1 wherein said desalinated water comprisesfreshwater.

4. The system of embodiment 1 wherein the first liquid column comprisesa body of water.

5. The system of embodiment 4 wherein the body of water comprises anocean, or a sea.

6. The system of embodiment 4 wherein the system comprises a firstelevation and a second elevation; and wherein the first elevationcomprises the elevation of the surface of a body of water; and whereinthe second elevation comprises an elevation lower than the firstelevation.

7. The system of embodiment 6 wherein a reverse osmosis desalinationmembrane is positioned at the second elevation.

8. The system of embodiment 1 wherein the first column comprises a bodyof water.

9. The system of embodiment 7 wherein the first column comprises a pipeconfigured to transfer the desalination feed from the first elevation tothe reverse osmosis desalination membrane at the second elevation.

10. The system of embodiment 7 wherein the second column comprises apipe configured to transfer desalinated water from the reverse osmosisdesalination membrane at the second elevation to an applicationrequiring desalinated water at or above the first elevation.

11. The system of embodiment 10 wherein said pipe comprises a riser.

12. The system of embodiment 6 wherein the second elevation has at leastone point which is greater than 1,000 meters lower than the firstelevation.

13. The system of embodiment 7 wherein a desalination concentrate isdischarged at an elevation within 50 meters of the elevation of thereverse osmosis membrane.

14. The system of embodiment 7 wherein a desalination concentrate isdischarged at an elevation which at least one point is equal to or lowerthan the elevation of the reverse osmosis membrane.

15. The system of embodiment 1 wherein the desalination feed ispre-treated.

16. The system of embodiment 1 wherein the desalination feed comprises afeed wherein at least a portion of dissolved gases are removed.

17. The system of embodiment 9 wherein the system further comprises apump configured to apply pressure to the desalination feed in the firstliquid column.

18. The system of embodiment 9 wherein the system further comprises adischarging fluid displacement energy storage system to apply pressureto the desalination feed in the first liquid column.

19. The system of embodiment 17 wherein the pump is at an elevationbetween the first elevation and the second elevation.

20. The system of embodiment 17 wherein the pump is at the secondelevation.

21. The system of embodiment 1 wherein the difference in gravitationalhydrostatic pressure is greater than 5 Bar.

22. The system of embodiment 1 wherein the system is configured tosupplement the difference in gravitational hydrostatic pressure by areduction of the pressure of the second liquid column.

23. The system of embodiment 22 wherein the reduction of the pressure ofthe second liquid column is reduced by transferring desalinated water inthe second liquid column into a lower pressure tank.

24. The system of embodiment 23 wherein the system is configured suchthat an internal pressure of the lower pressure tank is lower than thegravitational hydrostatic pressure associated with the elevationdifference between the elevation of the lower pressure tank and thesurface of the body of water.

25. The system of embodiment 23 wherein the system is configured suchthat an internal pressure of the lower pressure tank is lower than thegravitational hydrostatic pressure associated with the elevationdifference between the elevation of the lower pressure tank and theoutlet of the second liquid column.

26. The system of embodiment 23 wherein the system is configured suchthat the elevation of the lower pressure tank is above the elevation ofat least one desalination membrane.

27. The system of embodiment 23 wherein the system is configured suchthat the elevation of the lower pressure tank is lower than theelevation of the surface of the body of water by an elevation differenceabout equal to or greater than the hydrostatic head pressure fordesalinating desalination feed at a desired recovery ratio minus thegravitational hydrostatic pressure difference between the first liquidcolumn and the second liquid column.

28. The system of embodiment 23 wherein the system is configured suchthat the pressure of the lower pressure tank is maintained by a pumptransferring desalinated water from the lower pressure tank.

29. The system of embodiment 23 wherein the system is configured suchthat the pressure of the lower pressure tank is maintained by a pressureexchanger transferring desalinated water from the lower pressure tankpowered by pressure exchanging with a discharging fluid displacementenergy storage system.

30. A method for desalinating water comprising:

feeding saline water from a first liquid column comprising a body ofwater to a reverse osmosis desalination membrane; and

feeding the water through the reverse osmosis membrane at a pressuresufficient to provide desalinated water and forming a second liquidcolumn comprising desalinated water;

wherein at least a portion of the pressure is provided by a differencein gravitational hydrostatic pressure between the first liquid columnand the second liquid column due to a density difference between thefeed and the desalinated water.

Generating Power from Brine

1. A system for generating power comprising:

a brine source;

a pipe comprising a generator

and

a brine discharge outlet;

wherein the brine source is at a first elevation and the brine dischargeoutlet is at a second elevation; and

wherein the first elevation is higher than the second elevation; and

wherein the pipe connects the brine source at the first elevation to thebrine discharge outlet at the second elevation; and

wherein the brine discharge outlet and at least a portion of the pipeare configured to be located beneath a surface of a body of water; and

wherein power is generated by transferring brine from the brine sourceat the first elevation through the pipe comprising the generator to thebrine discharge outlet at the second elevation.

2. The system of embodiment 1 wherein the system is configured such thatpower is generated due to a gravitational hydrostatic pressuredifference between the brine in the pipe and the body of water due tothe density difference between the brine and water in the body of water.

3. The system of embodiment 1 wherein the body of water comprises a seaor ocean.

4. The system of embodiment 1 wherein the brine source comprises adesalination concentrate, or a desalination retentate.

5. The system of embodiment 1 wherein the brine source comprises adesalination system.

6. The system of embodiment 1 wherein the pipe comprises a riser.

7. The system of embodiment 1 wherein the system is configured such thatbrine is discharged into the body of water.

8. The system of embodiment 1 wherein the generator is located beneaththe surface of the water body.

9. The system of embodiment 5 wherein the generator generates power inthe form of electricity; and wherein the system is configured to employthe electricity to at least partially power the desalination system.

10. The system of embodiment 5 wherein at least a portion of thedesalination system is floating on the body of water.

11. The system of embodiment 5 wherein at least a portion of thedesalination system is beneath the surface of the body of water.

12. The system of embodiment 5 wherein at least a portion of thedesalination system is on land.

13. The system of embodiment 1 wherein the brine source comprises brinefrom an evaporation system.

14. The system of embodiment 1 wherein the generator comprises a powerexchanger and wherein the system is configured such that at least aportion of the power generated is employed to pressurize at least aportion of desalination feed.

15. The system of embodiment 1 wherein the discharge outlet comprisesone or more distributors to reduce a localized increase in salinityadjacent to the discharge outlet.

16. The system of embodiment 1 wherein the discharge outlet is at anelevation greater than 1000 meters below the elevation of the surface ofthe body of water.

17. The system of embodiment 1 wherein the difference in elevationbetween the first elevation and second elevation is greater than 1000meters.

18. The system of embodiment 1 wherein the generator is at an elevationwithin 50 meters of the discharge outlet.

19. The system of embodiment 5 wherein the desalination system isoperably connected to a power source by a subsea cable.

20. The system of embodiment 9 wherein the electricity is transferredfrom the generator to the desalination system with a subsea umbilical.

21. The system of embodiment 2 wherein the density difference betweenthe brine and the water in the body of water is greater than 0.005 kg/L.

22. The system of embodiment 1 wherein the system is configured to storeenergy by storing brine in a storage reservoir.

23. A method for generating power comprising:

transferring brine from a brine source at a first elevation through apipe comprising a generator to a brine discharge outlet at a secondelevation below a surface of a body of water; and

generating power using a gravitational hydrostatic pressure differencebetween the brine in the pipe and the water in the body of water due tothe density difference between the brine and the water in the body ofwater.

24. The method of embodiment 23 wherein the body of water comprises asea or ocean.

25. The method of embodiment 23 wherein the brine source comprises adesalination method.

26. The method of embodiment 23 wherein the pipe comprises a riser.

27. The method of embodiment 23 wherein the generator generates power inthe form of electricity; and wherein the method is configured to employthe electricity to at least partially power the desalination method.

28. The method of embodiment 23 wherein the generator comprises a powerexchanger and wherein the method is configured such that at least aportion of the power generated is employed to pressurize at least aportion of desalination feed.

29. The method of embodiment 23 wherein the system is configured tostore energy by storing brine in a storage reservoir.

30. The method of embodiment 23 wherein the brine source comprises brinefrom an evaporation method.

Seawater

As used herein “seawater” may include salinated water from an ocean orsea, as well as or salinated water from underground regions below sealevel, or above seawater, or any combination thereof such as producedwater and/or flowback water resulting from, for example, oil and gasoperations, or saline water from a saline aquifer, or saline watercomprising resident brine, or saline water from a salt cavern, or salinebrine pool, or subsea saline brine pool, or saline water from lithiumproduction, or saline water from potassium production, or saline waterfrom potash production, or saline water from evaporation, or salinewater from evaporation pond, or saline water from alkali saltproduction, or saline water from alkaline earth salt production, orsaline water from metal extraction, or saline water from mining, orsaline water comprising synthetic brine, or saline water comprisingman-made brine, or saline water comprising man-made salt water, orsaline water produced from a chemical production process, or salinewater produced from a material production process, or saline water froma cooling tower, or saline water from smoke stack blowdown, or salinewater from co2 capture, or saline water from co2 storage, or salinewater from water treatment, or saline water from acid gas scrubbing, orsaline water comprising a byproduct, or saline water comprising aneffluent, or any combination thereof. In some embodiments, “seawater”may include any water comprising a greater osmotic pressure thandeionized water.

Generating Power

In some embodiments, generating power may comprise providing power to adesalination system instead of, or in addition to, reverse osmosis,which may include, but are not limited to, one or more or anycombination of the following: vacuum distillation, or mechanical vaporcompression distillation, or membrane distillation, or vaporrecompression distillation, or multistage flash distillation, or heatpump driven distillation, or pressure driven membrane distillation, ormulti-effect desalination, or vapor compression desalination, or freezedesalination, or refrigeration based freeze desalination. Power may betransferred or exchanged by means of, for example, including, but notlimited to, one or more or any combination of the following: hydraulicexchange, or mechanical exchange, or pressure exchange, or powerexchange, or power transfer, or electrical motor, or turbo powerrecovery, or turbine, or direct mechanical exchange, or indirectmechanical exchange, or directly fluid flow, or aspirating valve, orventuri valve, or venturi effect based system, or venturi effect basedprocess, or fluid mixing, or any combination thereof.

Additional Notes

Note: In some embodiments, the low density fluid may comprise a densitywithin 0.005 kg/L, or 0.01 kg/L, or 0.015 kg/L, or 0.02 kg/L, or 0.025kg/L, or 0.03 kg/L, or 0.035 kg/L, or 0.04 kg/L, or 0.045 kg/L, or 0.05kg/L, or 0.055 kg/L, or 0.06 kg/L, or 0.065 kg/L, 0.07 kg/L, or 0.075kg/L, or 0.08 kg/L, or 0.085 kg/L, or 0.09 kg/L, or 0.095 kg/L, or 0.10kg/L, or 0.11 kg/L, or 0.12 kg/L, or 0.13 kg/L, or 0.14 kg/L, or 0.15kg/L, or any combination thereof of the density of water.

Note: In some embodiments, the low density fluid may comprise a densitywithin 0.005 kg/L, or 0.01 kg/L, or 0.015 kg/L, or 0.02 kg/L, or 0.025kg/L, or 0.03 kg/L, or 0.035 kg/L, or 0.04 kg/L, or 0.045 kg/L, or 0.05kg/L, or 0.055 kg/L, or 0.06 kg/L, or 0.065 kg/L, 0.07 kg/L, or 0.075kg/L, or 0.08 kg/L, or 0.085 kg/L, or 0.09 kg/L, or 0.095 kg/L, or 0.10kg/L, or 0.11 kg/L, or 0.12 kg/L, or 0.13 kg/L, or 0.14 kg/L, or 0.15kg/L, or any combination thereof of the density of seawater.

Note: In some embodiments, the pressure inside the lower elevationreservoir may be within 0.5%, or 1%, or 1.5%, or 2%, or 2.5%, or 3%, or3.5%, or 4%, or 4.5%, or 5%, or 5.5%, or 6%, or 6.5%, or 7%, or 7.5%, or8%, or 8.5%, or 9%, or 9.5%, or 10%, or 11%, or 12$, or 13%, or 14%, or15%, or 16%, or 17%, or 18%, or 19%, or 20%, or any combination thereofof the pressure of the adjacent body of water at the same elevation.

Note: Power may be transferred to or from a subsea or lower elevationpump or generator using a subsea power cable. Power may be transferredfrom a power source. Power may be transferred to a power consumer.

Note: Power sources may include, but are not limited to, onshore, oroffshore, or any combination thereof power sources. Power consumers mayinclude, but are not limited to, onshore, or offshore, or anycombination thereof power consumers. Power sources may include, but arenot limited to, power generator, or grid electricity, or power plant, orwind, or wind turbine, or solar, or solar PV, or solar thermal, or steamturbine, or rankine cycle, or power generation cycle, or tidal power, orwave power, or geothermal power, or power recovery, or thermal power, orheat engine power, or hydro power, or density difference power, orsalinity gradient power, or osmotic power, or recovered power, or storedpower, combustion derived power, or any combination thereof.

Note: Power consumers may include, but are not limited to, industry, orcommercial, or residential, or manufacturing, or chemicals, orresidential, or municipal, or offshore, or onshore, or aerospace, ortransport, or institutional, or data centers, or digital, or vehicle, orany combination thereof power consumer.

Power Generation Embodiments

1. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump; and

a generator;

wherein the pump, the generator, and the first and the second reservoirare operatively connected such that power is stored by displacing thefirst fluid in the first storage reservoir by pumping the second fluidin the second storage reservoir to the first storage reservoir and poweris generated or discharged by allowing the second fluid in the firststorage reservoir to return to the second storage reservoir; andwherein the first fluid is a liquid.2. The system of embodiment 1 wherein the system is a closed system.3. The system of embodiment 1 wherein the second storage reservoircomprises a rigid tank.4. The system of embodiment 1 wherein the first fluid comprisesfreshwater.5. The system of embodiment 1 wherein the first fluid comprises treatedseawater.6. The system of embodiment 1 wherein the first fluid has a densitywithin 0.05 kilogram per liter of the density of seawater.7. The system of embodiment 1 wherein the pressure inside the secondreservoir is within 10 percent of the pressure of the adjacent body ofwater at the same elevation.8. The system of embodiment 1 wherein the pump is at about the sameelevation as the second reservoir.9. The system of embodiment 1 wherein the generator is at about the sameelevation as the second reservoir.10. The system of embodiment 1 wherein the first fluid is transferredbetween the first reservoir and second reservoir using a pipe.11. The system of embodiment 10 wherein said pipe further comprises avalve.12. The system of embodiment 11 wherein said valve is employed tocontrol the pressure inside the second reservoir;

wherein said valve is opened to decrease the pressure inside the secondreservoir;

wherein said valve is closed to increase the pressure inside the secondreservoir.

13. The system of embodiment 1 wherein the second fluid comprises brine.

14. The system of embodiment 1 wherein the second fluid comprises asolid-liquid mixture.

15. The system of embodiment 1 wherein the second reservoir is locatedunderwater.

16. The system of embodiment 1 further comprising a subsea power cableconfigured to transfer electricity between the pump and the generator, apower source, and a power consumer.

17. The system of embodiment 1 wherein the second storage reservoircomprises at least one storage unit within it and wherein the system isconfigured such that the low density fluid and the high density fluidare storable within the same storage unit in the second storagereservoir.18. The system of embodiment 17 wherein the system is configured suchthat the low density fluid is located above the high density fluidwithin the storage unit.19. The system of embodiment 17 wherein the system is configured suchthat a fluid-fluid interface separates the low density fluid from thehigh density fluid in the storage unit.20. The system of embodiment 17 wherein the system is configured suchthat a chemocline or chemocline layer separates the low density fluidfrom the high density fluid.21. The system of embodiment 17 wherein the system is configured suchthat a physical divider separates the low density fluid from the highdensity fluid.22. The system of embodiment 21 wherein the system is configured suchthat the physical divider occupies at least 50% of the cross sectionalarea otherwise occupied by a fluid-fluid interface in the absence of thephysical divider.23. The system of embodiment 21 wherein the system is configured suchthat an elevation of the physical divider adjusts to follow a change inelevation of the fluid-fluid interface that would be present in theabsence of the physical divider.24. The system of embodiment 21 wherein the system is configured suchthat the physical divider is floating.25. The system of embodiment 21 wherein the system is configured suchthat the density of the physical divider is greater than the density ofthe low density fluid and less than the density of the high densityfluid.26. The system of embodiment 1 wherein the system is configured suchthat at least a portion of high density fluid mixes with at least aportion of low density fluid; and

wherein the system is configured such that at least a portion of highdensity fluid is removed from the low density fluid by separation.

27. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises at least one first reservoirstorage unit within it and the second storage reservoir comprises atleast one second reservoir storage unit within it and wherein the systemis configured such that the high density fluid and low density fluid arestored in the same storage units within the first storage reservoir andthe second storage reservoir.28. The system of embodiment 1 wherein the system is configured suchthat the first storage reservoir comprises a first and a second storageunit and wherein the system is configured such that the high densityfluid is stored within the first storage unit and the low density fluidcomprising a liquid is stored in the second storage unit.29. The system of embodiment 28 wherein the system is configured suchthat the first and the second storage unit are operably connected suchthat a gas is transferrable between the first and the second storageunit as a liquid enters a unit and displaces the gas.30. A system for storing and generating power comprising:

a first storage reservoir configured to store a first fluid;

a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid;

a pump; and

a generator;

wherein the pump, the generator, and the first and the second reservoirare operatively connected such that power is stored by displacing thefirst fluid in the first storage reservoir by pumping the second fluidin the second storage reservoir to the first storage reservoir and poweris generated or discharged by allowing the second fluid in the firststorage reservoir to return to the second storage reservoir; and

wherein the first fluid comprises water and the second fluid comprises afluid with a density greater than water.

What is claimed is:
 1. A system for storing and generating powercomprising: a first storage reservoir configured to store a first fluid;a second storage reservoir located at a lower elevation than the firststorage reservoir and configured to store a second fluid wherein saidsecond fluid has a higher density than the first fluid; a pump; and agenerator; wherein the pump, the generator, and the first and the secondreservoir are operatively connected such that power is stored bydisplacing the second fluid in the second storage reservoir by pumpingthe first fluid in the first storage reservoir to the second storagereservoir and power is generated or discharged by allowing the firstfluid in the second storage reservoir to return to the first storagereservoir; and wherein the first fluid is a liquid; and wherein thesystem further comprises a pressure exchanger near the second storagereservoir wherein said pressure exchanger is configured to reduce stressor required pressure resistance on the second storage reservoir.
 2. Thesystem of claim 1 wherein the second fluid is soluble in the firstfluid.
 3. The system of claim 2 wherein the system is configured suchthat at least a portion of the second fluid mixes with at least aportion of the first fluid.
 4. The system of claim 3 wherein the systemis configured such that at least a portion of the second fluid isremoved from the first fluid by separation.
 5. The system of claim 4wherein the system is configured such that said separation comprisesreverse osmosis, or forward osmosis, or distillation, or evaporation, orelectrodialysis, or gravitational separation, or decanting, orcoalescing, or centrifuge, or filtration, or cryodesalination, or freezedesalination, or solventing out, or precipitation, or extraction, orextractive distillation.
 6. The system of claim 2 wherein the system isconfigured such that at least a portion of the first fluid mixes with atleast a portion of the second fluid.
 7. The system of claim 6 whereinthe system is configured such that at least a portion of the first fluidis removed from the second fluid by separation.
 8. The system of claim 7wherein said separation comprises reverse osmosis, or forward osmosis,or distillation, or evaporation, or gravitational separation, ordecanting, or coalescing, or centrifuge, or filtration, orcryodesalination, or freeze desalination, or solventing out, orprecipitation, or extraction, or extractive distillation.
 9. The systemof claim 2 wherein the first fluid comprises water and the second fluidcomprises brine.
 10. The system of claim 1 wherein the second storagereservoir comprises at least one storage unit within it and wherein thesystem is configured such that the first fluid and the second fluid arestorable within the same storage unit in the second storage reservoir.11. The system of claim 10 wherein the system is configured such thatthe first fluid is located above the second fluid within the storageunit.
 12. The system of claim 10 wherein the system is configured suchthat a fluid-fluid interface separates the first fluid from the secondfluid in the storage unit.
 13. The system of claim 10 wherein the systemis configured such that a chemocline or chemocline layer separates thefirst fluid from the second fluid.
 14. The system of claim 10 whereinthe system is configured such that a physical divider separates thefirst fluid from the second fluid.
 15. The system of claim 14 whereinthe system is configured such that the physical divider occupies atleast 50% of the cross sectional area otherwise occupied by afluid-fluid interface in the absence of the physical divider.
 16. Thesystem of claim 14 wherein the system is configured such that anelevation of the physical divider adjusts to follow a change inelevation of the fluid-fluid interface that would be present in theabsence of the physical divider.
 17. The system of claim 14 wherein thesystem is configured such that the physical divider is floating.
 18. Thesystem of claim 14 wherein the system is configured such that thedensity of the physical divider is greater than the density of the firstfluid and less than the density of the second fluid.
 19. The system ofclaim 1 wherein the system is configured such that the first storagereservoir comprises at least one first reservoir storage unit within itand the second storage reservoir comprises at least one second reservoirstorage unit within it and wherein the system is configured such thatthe second fluid and the first fluid are stored in the same storageunits within the first storage reservoir and the second storagereservoir.
 20. The system of claim 1 wherein the system is configuredsuch that the first storage reservoir comprises a first and a secondstorage unit and wherein the system is configured such that the secondfluid is stored within the first storage unit and the first fluid isstored in the second storage unit.
 21. The system of claim 20 whereinthe second fluid comprises a liquid.
 22. The system of claim 21 whereinthe system is configured such that the first and the second storage unitare operably connected such that a gas is transferrable between thefirst and the second storage unit as liquid enters a unit and displacesthe gas.
 23. The system of claim 22 wherein the system is configuredsuch that a semi-permeable barrier allows the transfer of gas whilepreventing the transfer of liquid.
 24. The system of claim 1 wherein thesystem is configured such that the first storage reservoir is locatedunder a body of water.
 25. The system of claim 1 wherein the system isconfigured such that the first storage reservoir is at an elevationgreater than the surface of the body of water.
 26. The system of claim 1wherein the system is configured such that the first storage reservoircomprises a floating structure.
 27. The system of claim 1 wherein thefirst fluid or the second fluid comprises desalinated water.
 28. Thesystem of claim 1 wherein the first fluid or the second fluid comprisestreated seawater.
 29. The system of claim 1 wherein the first fluid isethanol.